Cuda context errors with s_flicker & Vegas Pro

Repro’d with VP 17 & 18

Lenovo Yoga 720 - Win 10 home
Core i7-7700 2.8Ghz quad core, 8 logical
16G ram
Intel HD 630 gpu - driver
Nvidia GTX 1050 gpu - Studio driver (462.31)
Sapphire 2021.5

When the 1050 is selected in prefs | video the Titles & Text event background will be opaque black when an s_flicker effect is enabled. If I change the gpu to the 630 or off, the background is transparent as expected.

Things I’ve tried:

o Driver cleaning and reinstall
o Sapphire uninstall and registry/file cleaning before reinstall
o Various amounts of preview ram, normally use 0
o Explicitly choose the gpu in the Sapphire config file
o Turn off gpu use in the s_effect options - this results in the background going transparent

Here’s the really fun part. When I originally created the project and applied s_flicker, it worked fine and the gpu selected was the 1050, which I use by default.

I re-opened the project the next day and discovered the text background was now opaque black.

I can repro this by:

o Choose the 1050 and restart VP
o New Project
o Add a Titles & Text event
o Add a track below and add a checkerboard event to the new track
o Apply s_flicker to the text and the background goes opaque

Sun May 9 11:02:15 2021: SBuild\sapphire-ofx\final-em64t\primitives\mem-manager.cxx:921: CUDA error: invalid argument
Sun May 9 11:02:15 2021: S_Flicker failed execution plan on 1920 x 1080 clip with 8 bit depth (temps 1920x1080)
Aborted from SBuild\sapphire-ofx\final-em64t\gpu\gpu-support.cxx:1340, type 6, code 0
Sun May 9 11:02:15 2021: ( (allocate-images :ref59.2g 3 2 gpu)
(convert-from-source 0 :ref59.2g)
(run-primitive 1 -1 :ref59.2g * :ref59.2g [ 0.955656 0.955656 0.955656 ] )
(convert-to-dest :ref59.2g)
(free-images :ref59.2g)
Sun May 9 11:02:15 2021: Info: GPU render failed for S_Flicker.Flicker. Falling back to CPU.