[warning] Undefined array key "title" Views.php:154

It seems like something is wrong with Views plugin definition. Can we get the full steps to reproduce this please?

Its very hard to reproduce as it comes from a migration from a site where title field is replaced by a separate title so occationally
the title field can actually be empty, therefore best solution is to make a bugfix for this so its fixed for future.

#4 would indicate that this is due to broken config (the title is missing when it should never be), so in that case this warning is doing exactly what it should do, warn you that your config isn't alright.

If there is a valid reason for title to be missing, only then should we add a check for it, otherwise we should assume it is set and throw a warning. Is there a way to get a missing title through normal use of the UI?

Yes by using title as field

This patch work with composer and auto patching like this

"extra": {
"enable-patching": true,
"patches": {
"drupal/core": {
"Undefined title":" https://www.drupal.org/files/issues/2023-06-19/undefined-key-title-33664... → "

No additional info provided so I'm closing this, if anyone is able to reproduce it please update the issue summary with steps.