I've been noticing this for a while, I just trashed my Resolume comp file and started over to rule out having weird stuff in my rather old composition file.
20hrs later (it's quite a big comp file, 32 columns and 4 layers) I'm on a fresh comp file in Resolume 4.1.11.
I first noticed it happening again when I started adding fx directly to a slot to affect everything under it. Added a Feedback effect into a slot and got the load/blank thing like in the above video. Once it starts half the Source Effects will stop loading, failed FX can be different depending on the comp. My last comp file I couldn't load Line Scape, Lines and Gradient. Whenever copying and pasting between comps it would lose problematic effects like Feedback.
On this new comp when it starts the problem is only in the main comp, if I tab to a empty comp any failed source will load fine. Just now I lost Feedback, Gradient and Static.. restarted and I can add again.
I found in my last comp those source effects disappear so regularly that you can't really count on them, eventually you just can't load them, copy and pasting between comps will infect the new comp with the problem.