Decryption issues only on some files since update (14.0.3)

Nextcloud version: 14.0.3
mySQL: 5.6.42
PHP version: 7.1

The issue you are facing:

Trying to download from folder-pane gives following error
Can’t read file multikeydecrypt with share key failed:error:0407109F:rsa routines:RSA_padding_check_PKCS1_type_2:pkcs decoding error
(Moving to a new folder from folder-pane works, but trying to download from new folder gives same error,)

Trying to download from preview (preview works) gives following error:
Sorry, this file could not be found. Reasons might be: the wrong file ID was provided the file was removed the file is corrupt the encryption key is missing Here is the error message returned by the server: There was a problem accessing the file (404) For more information, please contact your friendly Nextcloud administrator.

Trying to copy from folder-pane gives following error:
Could not copy “IMG_00000000_000000_000.jpg”

Only on files uploaded before the update to nc14.0.3

Is this the first time you’ve seen this error?: Yes.

Steps to replicate it: Not able to

The output of your Nextcloud log in Admin > Logging: Nothing in referece to filesystem.

Anyone any idea how to get back my files?