Thank you so much for reporting this. I've had a quick look.
I'm only able to reproduce this in GZDoom. UZDoom (which I would recommend going forward anyway) types a few warnings but doesn't crash. I can briefly see the spawn sprite in the weapon wheel, so I don't think it's missing an image (the weapon wheel is deisgned to default to the pickup sprite if an inventory sprite hasn't been assigned).
Accessing the weapon wheel while picking up other artifacts like this one doesn't seem to have this problem, so there's something different about this one. I'll go through the code carefully this weekend and see what's going on.
Thanks again!
edit: Turns out it's because the pickup sprite is animated, the wheel can't handle that. Giving it a single frame inventory icon fixed it. The fix will be included in the next update.