I'm facing the same issue. And one fact behind Snapchat’s success is its cool filters, In which user can change the face within no time at all. But sometimes these filters do not work. But while searching the web I found the solution to fix the Snapchat filter not working Issue.
mine was the same, I rang Sony tonight. They tell the problem is the apps (snapchat) since the update on Sony, this means the apps are now needing to be updated so we need to co tact the app developers. So he said u less snapchat sorts it out. It won't be fixed anytime soon.
I have the same problem. I was using the snap filters and lenses on Xperia for years with no problems.... Then 6 months ago stopped working. Xperia XA1 and older Xperia. Have contacted the app developers and they have been useless so far. If anyone has a solution for this I would love to hear it. Phone is updated and latest version installed of all apps.