I thought these actions previously worked to loop through and process each substring. However, I don't recall making any changes, but I'm not 100% certain it has worked since upgrading to Keyboard Maestro 10.0.1 on macOS 11.6.1 either. I'm having difficulties debugging why the remaining substrings or Release_Item(s) are not found and would appreciate some suggestions to check. It is probably something obvious that I'm missing since Regex101.com appears to capture each Release_Item, but the For Each action only captures the first substring.
Your regex to break up the data into substrings starts out with ^ which anchors it to the beginning of the string. Only the first match at the beginning of Data will match it. Remove the ^ at the beginning and it may work. May because when I did that, I only matched the first 2 strings. I think there is something wrong in your regex (or my typing of it) that caused the last one to mismatch.
That matched all 3 strings for me. It doesn't try to be as precise as yours so it may not actually work for you. Couple of things I noticed:
You don't have to escape every "weird" character, I've been finding lately if I do this it breaks the regex. So the ⌘ doesn't need to be \⌘
I removed the grouping parentheses as they aren't used for anything in this particular regex (it worked with them in just the same).
I see you're using [0-9] in some places so I assume you know that means any character in the range of, but you can stack as many additional characters into the brackets as you want and it'll work as "find one of any of these characters) so where I do [A-Z0-9/-. ]+ that means any upper case letter, any digit 0 to 9 the forward slash, the dash (has to be escaped) the period (also escaped), or a space.
In my initial posting, I indicated that I "thought" this action worked previously. In fact, I know it has worked previously for a long time and I have not modified this macro and have used it for some time. It is a very long macro and I thought it was not useful to post the other unrelated actions, but I will include full macros when requesting support in the future.
Thanks for the instruction on posting text that needs to be seen verbatim and the regex recommendations for the resolution of my issue. As suggested, removing the caret (^) enabled the For Each action to loop through each substring. Still not sure what changed.