Auto switch only when all recepients match with a domain not working

[stmichaelis]

I have the exact use case fitting this implemented feature request: #51

Unfortunately, this does not seem to work (completely) for me. Simplified scenario: I have a signature for external recipients, which is set as default, and a signature for internal recipients. The latter should be used in cases where all addressees are internal only. The "auto switch" field is populated like *xyz.de,*xyz.com as multiple domains count as internal.

The signature switches fine when adding emails matching the first pattern (ending on xyz.de). But the signature still switches back to external once I add another email matching the second pattern, treating this as external.

Workaround:
Trying to understand the source code in

mozext/signatureswitch-me/src/background/background.js

Line 574 in 2d8e50e

let anyAutoSwitchItemMatchesWithAllRecipients = (autoSwitchItems, recipients) => {

and the way regexp are used for the matching, I replaced the comma separating email patterns with | in the auto switch field, which should be the regexp-OR operator for matching multiple patterns?
Using this separator, the auto switch works as intended. I wonder about the exact why and implications, and why the pattern matching works for the other case, when the "all recipients need to match one of the criteria" is unchecked.