Greetings EmT,
It was directly after I upgraded to the V2 versions of the Affinity Apps. I ported my 3rd party resources from the V1 software to the V2 Apps. I didn't uninstall the V1 Affinity Apps for a week or so and used the V2 Apps to make sure they were working as expected. When I was confident V2 was working properly, I uninstalled the V1 Apps. After that, the next time I opened Affinity Designer V2 the raster brushes and color swatches were missing. I opened Affinity Photo V2 and the raster brushes and color swatches were missing as well. In addition, I was unable to import raster brushes or color swatches into Designer or Photo.
The apps didn't crash nor was I using or editing brushes.
I followed the advice of walt.farrell (see posts above) and was able to reset the apps and reload my raster brushes and color swatches. Everything has been working normally since then.
I hope this information is helpful.