Thank you.
The problem is that Audacity 3.7.3 (and 3.7.5) import OGG files as 16-bit tracks. Unfortunately the Muse Group team decided to remove the sample format information from the panel on the left end of the track, so there is no visible indication that it has done this.
Comparing with Audacity 3.4.2: OGG files are imported as 32-bit float and the sample format is shown in the panel on the left end of the track:
Technical description:
Because Audacity processes audio with 32-bit float precision, the 16-bit track cannot hold the exact 32-bit sample values, so values are rounded to 16-bit values. dither is applied automatically so as to avoid periodic quantization noise.
Solution:
Immediately after importing any OGG format track, change the track’s sample format to 32-bit float.
Update:
I’ve logged the bug here: OGG files imported as 16-bit · Issue #9950 · audacity/audacity · GitHub