Certain particle systems freeze when rendered in Fullscreen mode during PIE with Text Block added within Widget Blueprint. From what I could tell it is the GPU particles that are freezing.
Note I noticed you can temporarily update the particle system by toggling the console command using the tilde (~) key. The particle will freeze again not long after, but updating the viewport re-triggers the particle system to be updated in real-time.
I have attached some screenshots of my level blueprint setup for reference on how to reproduce the issue.
1. Open 'Effects' map in Content Examples project.
2. Create new Widget Blueprint with Text Block
3. Open Level Blueprint and add Widget Blueprint on Event Begin play.
4. Press PIE
5. Walk up to the Global Vector Field example 2.2.
6. Toggle Fullscreen mode (F11).
Outcome After a few seconds the particle system freezes
Expected Particle systems continue to update in real time.
NOTE I was only able to repro this bug consistently after disabling a plugin(Substance) and restarting the editor. The bug also shows up if you enable a plugin and restart editor. - Ed
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