First of all LS 6.2.11 is quite "old" already (has been released somewhen in 2023, so it is over 12 months old) and there have been quite a few releases (with bug fixes and security patches) since. The current version is LS 6.8.2, so you can see that there must have been quite a few things going on since 6.2.11.
So before trying to start to check if this is a bug, I highly recommend to upgrade to the latest version and see if this still persists. In my opinion, it doesn't make sense to try to fix a bug that might actually already be fixed in new versions.
Should this persist after the updating to the latest version, then we should check systematically, when and where this error appears exactly.
Once you did the update and the error persists, it is important to provide as much information as possible (e.g. server enviroment this is running on, vor example Linux vs Windows server, etc.)
here a link to the same error in LS5 a while ago:
forums.limesurvey.org/forum/design-issue...ts-argument-2-$array
No real solution so far. But it doesn't seem to be a Limesurvey specific error, because if you post the error string, it seems to have impact on many other platforms as well (Drupal, Prestashop, etc), which leads me to the conclusion, that it might have more to do with the server configuration, than with the actually websoftware. But I am no expert on this. Let's see what for example Denis has to say about this.
