Change of speed on particular part of track (not entire)

Hi
Is there a known problem that when uploading or downloading a file, only particular parts of the track are changed, but the total time of the track remains unchanged? This means that several faster and, of course, one slower passage can follow one another, whereby this only happens in isolated places and not the entire piece.
This would also be random and not determinable (once at the beginning then another time in the middle etc.)

Only the selected audio will be changed by an effect.

I don’t think that’s possible, especially if you want offsetting fast & slow parts so the overall playing time isn’t changed. And you probably wouldn’t be happy with truly-random results…

You can figure-out a way to make some random numbers (pull numbers out of a hat, or use a spreadsheet’s random function, and apply those results manually.

Thank you doug.
Someone mentioned, that this is a bug in Audacity 3.5.1 when not saved properly. For me it is strange too.

Yes, this issue can occur due to network fluctuations or server-side performance variations during file transfers. These inconsistencies in speed might cause certain segments to be faster or slower, but the overall transfer time remains unchanged. This randomness is often caused by varying network congestion or resource allocation at different times.