Hi @Jon P, i don't have any issues or bugreports with my fontmanager upon file load. It is really funny, because it perfectly works with 1.7.3.
I forgot to say to have the same issue with designer and photo.
When I clicked in the Textmenu and choosed a specific fontfamily it immediately switch to another font randomly.
When I took a look into the textmanager in affinity publisher, he knew the font used in the projects, but had the status as missing, and did already substitute another font. But choosing another font, it doesn't matter which one, status was missing and the font was randomly substituted by another one again. In other programs e.g Photoshop the font is not missing.
Not sure if this is the answer you are waiting for, I hope it helps.
Many thanks,
Paul