AF volume loss when using SPLIT

Hello FLEX users!
For years and different FLEX-6K I've been wondering about a clearly noticeable AF loss in SPLIT mode, which I tried to compensate more or less well by different AF settings of VFO-A and VFO-B. In the end I almost came to terms with it and attributed it to my age-related hearing loss (although I didn't have this shortcoming with other TRXes, such as IC-7600, etc.)...
...and over all these years I never read/found anything about this "effect" here in the FLEX-Forum - so it really seemed to concern only me...  :-)
But now I noticed more or less by chance how drastic the hearing difference really is! Only with VFO-A the signal is clear and loud audible (according to the settings!) - but as soon as you activate VFO-B via SPLIT, it gets much quieter! But how bad it really is, you can see when you listen to the same signal with VFO-B (VFO-A is muted!), the same signal is even quieter and above all much more dull and frequency-cut...
If you do the same listening test not by SPLIT activation but by switching on a 2nd pan adapter (which is now VFO-B), this signal is loud and clear on both VFO's and the loss effect described above does not occur, instead you can record different signals on both VFO's - CW pileups are now not only a pleasure for the eyes but also for the ears!   :-)

Conclusion: I think this is a real bug of the FLEX-6K series (I don't know if it's hard- or software) and should be fixed!
But to make this a topic for FLEX as well, several other FLEX operators would have to confirm this bug and/or report their experiences...

Helmut, OE8TTR