@Canapin you overlooked my issue: it’s not about repeated words, but about repeated pattern replacement of a single word: the URL contains the pattern to be replaced twice.
Since the /g pattern substitution option is default in the plugin, it should apply to all occurrences of $1 in the replacement, not just for the first one.
It’s a different case than having the keyword appear multiple times in a sentence, line, or paragraph. The replacement should account for multiple occurrences of the selection.