I tried it, see screenshot.
Automation prezision set to 1 sample.
Dark green track is source with hard automation.
Light Track is audio export, no VCA involved. (sample accurate)
Red Track with source Track assigned to VCA, no Automation on VCA.
Yellow Track is with source Track assigned to VCA but “VCA connection deactivated”.
Blue Track is with source Track unassigned again from VCA.
Roughly measured differences in the area of 200-400 samples. About 4-8ms difference at48kHz.
Tested on my Laptop with ASIO4all and 512 Samples Buffersize.
This is not sample accurate automation.