Steps to reproduce:

1. Create user macro: {$TEST} = VALUE
2. Re-name one of the active items, change name to: {{$TEST}.regsub("VALUE", "TEST")}
3. Save the changes
4. Open Monitoring-> Latest data
5. Check that name of the item is "TEST"
6. Edit the same item
7. Change the name to: Item name {{$TEST}.regsub("VALUE", "TEST")}
8. See the result in Latest data

Result:
The macro function is not having any affect on the item's name, the item name is: Item name VALUE.

Expected:
Macro function should work as expected, and item's name should change to: Item name TEST.

See video: