It looks like the crash occurs not in load_stimulus but rather during update_stimulus_display (possibly immediately after the load_stimulus, although I can't tell from the crash log). It also looks like part of the load is happening asynchronously and hasn't completed yet. This may be the cause of the crash, which occurs inside the graphics driver.
Would it be possible to add a short wait (maybe 100ms) right after the load_stimulus actions? That should give the asynchronous part of the load (which MWorks unfortunately has no knowledge of or control over) time to finish.
Alternatively, I suspect this wouldn't be an issue with a recent nightly build. MWorks' stimulus rendering code has been modernized and basically completely rewritten since the build you're using, and it wouldn't even use the driver that's triggering this crash.
OK. Is it just MWClient crashing now, or does MWServer crash, too?
Regarding MATLAB, MWorks' MATLAB tools and MWClient's MATLAB window are currently built against MATLAB R2018b. With the older MWorks build you were using, the MATLAB stuff was built against R2017b. It looks like you're using MATLAB R2014b, so I'm surprised that things worked even with the older build. Switching to R2018b or later should fix things.
Ok- we'll close the experiment going forward- but I'll grab an error report
next time and send it.
Also- we have a resurgence of the ehFeedback error with the new nightly.
We merged your pull request from July that should fix this- so maybe the
nightly introduces some new issue? Would be great if you could check on
this when you're back in town.
Have a good holiday,