I tried manually entering settings in Beta 61 to replicate the imported settings from 8.34, and was able to get the same result (no differences at start of track from first run of Stereo Tool).
Basically, the differences from User_Default_b61.sts
are that both AutoEQ's are turned off, Low Level Boost is turned off, and Basstadizer is set to Legacy (i.e., Bass Boost instead of Basstadizer).
Turning on Basstadizer has no effect on the issue, so that should be eliminated.
Turning on Low Level Boost WITH or WITHOUT enabling Legacy mode results in the issue happening.
The issue also happens with ONE or BOTH of the AutoEQ's turned on, WITH or WITHOUT Legacy mode.
So this problem is tied to those three modules. If all three (AutoEQ, BassEQ, & Low Level Boost) are off, then the problem doesn't happen.