The problem we're running into was brought up by someone else in the forums back in 2017:

https://community.adobe.com/t5/Premiere-Pro/Why-is-Premiere-linking-the-wrong-clip/m-p/10646862#M229918

In our environment, we edit off of our server, and have done so for a long time now, without issue. All systems used to be Macs, but we've started introducing some PC systems into the mix, and now we're starting to run into complications.

This particular complication is around Premiere relinking to the incorrect media when switching between system OS.

1) Create a project in OS A (could be Mac or Windows), and then edit something.
2) Replace an asset in the timeline.
3) Save the project,
4) Open the same project on OS B (the opposite of whichever you chose in Step 1).
5) Marvel as your clip (replaced in Step 2) is linked to the old media.

This only seems to happen with media which have undergone the "Replace Footage" treatment, and this never used to happen when we were only using the one OS.

System Information:

All systems are running the latest Premiere release (13.1.5)

PC:
Windows 10 (1903)
Intel i9-9900X
64 GB RAM
Nvidia RTX 2070 (431.36)

Mac:
OS 10.14.6
iMac Retina 5k, 27-inch, late 2014
4 GHz i7
32 GB RAM
AMD Radeon R9 4GB

This has not been fixed even though Adobe has claimed to fix this.

I have the media in one master project. My assistant has a their shared project. I open a small sequence from that project and drag the media from it it into my main project. EVEN THOUGH I ALREADY HAVE ALL THE MEDIA, I STILL GET DUPLICATED MEDIA. And on top of that it creates a separate folder for each small clip of footage. Take a look at the attached screenshot.

This is horrible. Fix this asap please. What's the point of shared projects if we can't move media back and forth between them?

I stopped editing for several months and recently came back to it. What I noticed is that Pr seems to have some issues importing the same types of footage that it previous had no issues with: 4K/60 h.264 files that are 5-6GB in size. Previously, Pr would just import them in with no issue. Now, Pr seems to lock up during the import, and again when I try to put that footage on the timeline for the first time.

During this "lock up", one CPU core from my 7900X is pushed right to 100%. The rest of them are at or near idle. It's a different core each time that goes to 100%, but it happens every time.

System:
Windows 10 Pro v.1903
Core i9 7900X OC'd (and water cooled)
2 x nVidia 2080Ti GPUs OC'd (and water cooled)
64GB DDR4 OC'd
SSD pairs in RAID0
HDD pairs in RAID0 (7200 RPM)
Scratch space on an M.2 drive

None of the resources are being taxed except that single CPU core. If there's any other info I can provide that might help get to the bottom of this, let me know!

I have been dealing with this issue for a while, I have read every relevant topic on this forum to no avail.

Windows 10
32 GB ram i7 500GB SSD
GeForce RTX 2060

So this only happen occasionally, Id say 1 out of every 35 attempts of dragging clips to the media files in Premire, but sometimes if crashes when I only open up the file explorer, before I even try to drag a clip in. Usually the clips are MP4 since it sometimes happens when I just open file explorer it may not matter the type of file.

One thread seemed to suggest that changing the sequence codec to prores 422 instead of "ifram only MPEG" which appears to be my default for some reason. But this has not helped.

Anyway I have set me autosave to every minute so that has kept me from loosing too much time but I edit all day every day and It happes probably 4 or 5 times a day so I would love a fix.

Setup:
Windows 10
PPro 13.1.3
Blackmagic RAW v1.5

Editing a feature that was begun on OS X PPro 13.0.1 and just migrated media/project files to a faster Win10 machine. For various reasons, had to do something I rarely do and that is upgrade to PPro 13.1.3 mid-project. Using the new BRAW codec for Premiere, I unlinked from the transcoded ProRes files I was previously editing on and linked media directly to the braw files directly taken from a BMPCC4K camera.

To my horror, all my sequences and synced clips of the entire movie are off by up to 1.5 minutes. Timecode displayed in my Program Monitor are DIFFERENT than the timecodes in my footage bin (i.e. "Media Start").

I've since read many of the posts here and elsewhere and see there was a problem with recent versions of Premiere in misrepresenting timecode, which is absolutely baffling.

I tried a workaround suggested to make a New Project and use the Media Browser to import clips and/or sequences from the older project. Did not work for me.

Okay fine- proxy/transcoded workflow, migration from Mac>PC, upgrading in the middle of a project, lots of variables, right?

So... keeping it simple I tried making a New Project in Premiere 13.1.3 and via media browser importing several BRAW clips into this lean, brand-new project. Checked the 1st frame of each clip within Premiere. Also, using the BRAW Player v1.5, I opened the same clip(s) to compare side-by-side.

Starting timecodes are ALL different in Premiere varying between a few seconds to minutes while viewing the same files!

What is going on? It can't just be me.

I don't feel comfortable proceeding if Premiere is STILL displaying/reporting the wrong timecodes. I will eventually be needing to do some roundtrips and handoffs to others so incorrect timecode is inexcusable. I'm devastated at the prospect we may have to re-sync and manually reconform all our edits, since the previous timecodes are useless.

TL;DR
Reconnected a large project in Premiere only to find all clips suddenly out of sync with externally recorded audio. A much simpler test (see first comment below) shows that Premiere 13.1.3 is "making up" a false timecode while BRAW Player & Resolve report the correct timecode. Any kind of conforming will be next to impossible until this is fixed.

Just like you can re-link a file to one with different timecode than the version in the project, you should be able to link a proxy file to a master clip with different audio channels than the original. Just like with TC, if there is 4 channels in original clip and proxy clip only has 2 channels, the slash marks simply appear in channels 3 and 4.

THIS IS IMPORTANT because the H.264 spec only supports 2 channels. ALMOST ALL CAMERAS shoot with 4 channels. H264 is IDEAL proxy format if you're taking project to edit mobile (ie to the beach) or especially to transfer online to an assistant. So, effectively, this restriction does not allow h.264 proxies to be used, which is dumb.