I’d look for a restrictor in your pneumatic lines, they were used to slow down overactive various back in the day before we got good total energy probes. Another issue could be 3 various sharing one total energy input, a slight decrease in pressure seen in the first vario can cause a slight flow from the other various, in the opposite direction. Add a restrictor to this mess and you can get trapped pressures in the system. No more than 2 various should be sharing your total energy probe. I fly with a fairly fast electric vario with audio and a slow second vario, don’t feel I need any more.
Hope this helps,
JJ