Error with piwigo 15

[mdlaat]

Hi, thank you for this plugin.
After updating piwigo to 15.0, I get these errors, also after trying to reinstall piwigo-openstreetmap:

Warning: file_put_contents(./osmmap.php): Failed to open stream: Permission denied in /config/www/plugins/piwigo-openstreetmap/maintain.class.php on line 161

Fatal error: Uncaught --> Smarty: unable to write file ./osmmap.php <-- thrown in /config/www/plugins/piwigo-openstreetmap/maintain.class.php on line 164

My piwigo was running otherwise fine in docker, as non-root.
Help appreciated, thank you.

[addich]

Same here. and still the case after deactivation, delete and reinstall.
is there any information I can share helping for find the issue?