Instrument Sound decreases after several minutes

Odd problem: I load one or several instruments into Hal 6. After about 10 minutes, the instrument I’m actively using goes down in volume about 10dB (my estimate). Other instruments are fine. My work-around is the delete and reload only that instrument, and the volume returns to normal.

Only recent changes are installing T-Guitar and a bunch more E/W samples. I did ensure latest firmware-sw on my UR824.

Cheers,
Pat

Been Busy.
Volume on a Halion instrument-midi chnl drops about 10dB.
If I load another channel with same instrument, volume is good, for a while, then it goes down also.
All levels at the Hal level, instrument level, and track level are the same.
???