Currently, there are four threads about this issue, not just this one. So it is affecting more people than this list suggests. The quickest workaround?... I have found that having the sequence open and visible in the timeline before you duplicate it yields a correct result every time (so far). If it's not open, a duplicated sequence will usually have missing data in all audio compressors. While I called it the "quickest" workaround, it certainly isn't quick, as I still take the time to check every compressor in every duplicated sequence, else I could ultimately loose a client, and my reputation. Adobe, please acknowledge on all four threads that you are hearing us.

Same here guys, What is up Adobe?? please help. Ver 12.1.2

It also happens across systems - just received a sequence from my co-editor - we have a Tube-Modeled Compressor effect with the Voice Thickener preset on every dialogue clip.

Copied his sequence into my project, opened it up and every single compressor effect was reset to zero.

The majority of Premiere Pro users may not go near compression effects, but for those of us who do and whose daily income depends on an NLE that is robust and allows you to work fast - this is a HUGE DEAL.

After I reported the tube-modeled compressor resetting itself to zero when a sequence is duplicated, it's happening to my co-editor on his system as well. Seems to be isolated to the family of compression effects. Very frustrating. We use compressors a lot, it's an incredibly annoying bug.

Getting the same issue with a Multiband Compressor effect on the audio track.

For me, I've noticed that it only seems to wreck the compressors (if there are other effects impacted, I've missed them), so when I duplicate a track (and have my compressor reset), I simply check the previous sequence and manually re-input the settings to the new sequence.

It's a thousand miles from ideal, but it's the fastest solution that I have found so far.

Same here! Terrible!
with me, its random sometimes duplicating a sequence with audio track effects is resetting them sometimes it's not.
my workaround (when I notice the bug) - is to re-duplicate the source timeline delete all clips and paste the contents of the duplicated sequence that the track effects has been rest...
terrible...

I just posted a comment about this exact same issue. It only started for me in 12.1, and continues in 12.1.1.

Incredibly frustrating bug. I'm genuinely hating 12.1/12.1.1

This is happening to me as well. I duplicate sequences often, for version control (it's an absolutely essential part of my workflow), and, because it's not possible to save or copy track effect settings, I'm having to manually recreate all my audio track effects, sometimes several times a day. Has anybody discovered a work-around while we wait for this bug to be fixed?

This is happening to me too, exactly what OP described.

this is also happening when copying and pasting a Sequence

same in version 12.1.1
this cc 2018 April update is driving me crazy!