Multiple fields remove button fails for Smart Date field with Recurrence enabled

Experiencing this issue also.

Drupal: 9.5.9
Smart date: 4.0.2
Multiple Fields Remove Button: 8.x-2.2

When I go to remove a date with a recurring date rule it just says 'please wait...' and then nothing happens. No error, just doesn't remove it.

I recently installed the module with this configuration and it works for me:

Drupal 10.0.9
Smart Date 4.0.2
Multiple Fields Remove Button 8.x-2.2

This issue is reproducible in Smart Date 4.0.3, but I noticed that the patch provided by @mandclu partially applies and the partial application fixes the issue. Here is a new version of the patch with the change to SmartDateWidgetBase.php that was in the original patch but was not changed in the source code.

Note that this issue is also reproducible in 4.1.0-rc6. I tried updating in case it would resolve the issue but it didn't, and the patch is not compatible with that version. The only resolution that has worked for me has been to use version 4.0.3 and apply the change to SmartDateWidgetBase.php that was in the original patch.

Issue persists for me with:

Drupal: 10.4.1
Smart Date: 4.2.3
Multiple Fields Remove Button: 8.x-2.2

Just curious -- for people still affected by this, do you perhaps have ECA Form module enabled? I'm wondering if it's related to this: 🐛 ECA Form breaks complex IEF widget Active

I was just testing and see it on a core field--

To repro:
1. Disable smart_date, multiple_fields_remove_button.
2. Create two new fields:
2.a. Date and time (Date, multiple)
2.b. Date and time (Timestamp, multiple)

Add multiple values to each field on a node, then save it.
Edit the node and try removing values.

Result:
1. Can remove all Date values
2. Cannot remove all Timestamp values

I could be wrong but, looks like core (maybe multiple_fields_remove_button too) need an update. I'll try and look more.

Versions: Drupal version : 10.4.5