Graphics card memory doesn't seem to be released after encoding with VoukoderPro. Up to and including v0.7.2.6.
I have GPU globally disabled in Vegas 20 (because it slows rendering down - it's a Vegas thing!).
Typically I'm running 2 instances of Vegas in parallel, and rendering in both simultaneously using NVENC through VoukoderPro. My first pair of VoPro renders usually use about 3 GB of VRAM. When the renders end, the memory is not released. If I run a second set of renders, now usage is up to 6 GB. If I run a third set of renders, now usage is 9 GB (paged, my current card is 8 GB). And so on.
This behavior has not been observed with other render methods, including Voukoder 13.0.2. These other methods release the video memory as soon as the render is stopped/finished.
The memory is released if I restart Vegas.