Joomla Textfilters corrupt Links in editor fields

Since the Upgrade to Joomla 4 and FlexiContent 4, my client can't save content with links any more without the links being corrupted.
This is what she enters / what the editor creates when she enters content:  This is what we see after saving
This is the setup to reconstruct it: 

• User group: Administrator
• Textfilter in global config for this user group: any, but we used the "custom blocked elements"
• Editor: JCE Editor Pro v. 2.9.33
• Joomla: 4.2.6
• Flexicontent: 4.1.3 and then also with 4.1.5 (no difference after the update)
• Browser/OS: Windows with Edge Browser, but it behaves the same in all browsers (server side issue)

To see the issue, you need to reload after saving, at first it looks fine (the content in the editor seems to be cached or come from the user input, not from the latest database version). If you save and then reload the edit form, the links are corrupted.

I have tried the same with Joomla and JCE without FlexiContent and then it works.
At the moment, my workaround is to disable all Filters in global config for the admin group, which is a decrease in security in theory but at least saving is possible without issues this way.

its only in description field or in all text area field ?

I tested that. The problem appears in all textarea fields, not only in the description.
Interestingly, it happens with some texts, but not all.

for example with this one, it DOES happen:
and with this one it does NOT:
They seem pretty similar to me.

in all text area it can be a joomla rules did you check it ?