SMIME css breaks after private key upload

[boekhorstb1]

When I upload a SMIME private key the UI suddenly breaks. Looks like not static assets are loaded.

[boekhorstb1]

[boekhorstb1]

Allright I tried some debugging and found out the following:

• adding public smime keys works
• adding private smime keys does NOT work (breaks css)
• just removing the content of vendor/horde/imp/templates/prefs/smimeprivatekey.html.php smimepublickey.html.php does not work
• I wondered if decrypt in the function getPrivateSmimeKey does something wrong, but the return values look good and simply removing the return of getPrivateSmimeKey does not change anything. So maybe its an issue with the session? I noted that some stuff gets saved there.

The error in network tab of firefox says 500, so something in the backend goes wrong. But I dont know what :)
Consequence of that is that js and css is not loaded at all