The search term variable, %s, is only evaluated once per bang

I want to add a custom bang for Omnivore, and I need to use the given search term twice:
https://omnivore.app/home?q=in:all (label:%s OR %s):

When using the bang, unfortunately, only the first occurrence of %s is replaced with the actual search term (e.g., !oml abc becomes https://omnivore.app/home?q=in:all (label:abc OR %s) instead of https://omnivore.app/home?q=in:all (label:abc OR abc)). (It also doesn't matter if there are brackets or not, the problem remains the same.)

%s gets evaluated only once, while it should be replaced at all occurrences: