Partly. Remember, if you have the attack all the way down, that actually equals the SAME amplitude change but at an extremely fast rate. Also, if the envelopes seem TOO punchy (sounds like that's the problem), adjust the CV input level on the VCA downward...try to NOT run VCAs wide-open, as a rule.
What's actually going on is that, without turning the decay up, you've got an envelope outputted that's actually too rapid for the VCA's latency. But when you increase the decay TIME (and not amplitude!), you actually are outputting the full amplitude swing on attack slowly enough to overcome the VCA latency. It SEEMS like the problem is the EG...but it's actually the CV input level to the VCA. Reducing the VCA's CV input level will get that under control.
FYI, the difference between linear and exponential actually has to do with whether or not you're using the VCA for CV/mod use, or for audio. Linear VCAs change level in a 1:1 proportion to the CV level. But exponential VCAs change level in an asymptotic curve that mirrors our perception of absolute loudness...which also works in an exponential manner, just like the decibel scale which measures loudness according to the same physics circumstances as how we perceive it. As a result, you use exponential VCA curves pretty much for AUDIO ONLY...as the exponential curve distorts the 1:1 scaling that VCAs...and their normal "client" signals...require for linear voltage changes.