Due to the AI integration and processes behind Prisma, some filters require your device to be online. If you happen to have a slower connection or weak signal, it is going to take even longer for those filters to load.
With Prisma’s online filters having issues, you might just want to stick to the offline options, at least until you’re in a better area or your connection has improved. A quick way to tell the difference is to turn your device on Airplane Mode. Without network access, the app will gray-out those filters that require an internet connection to function.