Do you have the same issue if you follow the OP’s steps to reproduce it?
YES
Provide extra information to complete the original description of the issue:
Behind the MSFS simulated ‘cloud lift’ is clearly a complicated formula including the density, base-to-top altitude, wind strength(??) but as the OP states the combination of these factors over the recent sim updates has resulted in a REDUCTION of lift in the range we’d expect for ‘normal’ Summer cumulus, e.g. 6000-foot cloud heights and a density of 1. Setting more extreme settings in SU12 Beta can give adequate lift but significantly impacts the visual appeal of the cloudscape.