azure - Strange replacement behaviour (braces + parentheses) -

i'm using azure translator (https://www.microsoft.com/en-us/translator/translatorapi.aspx). if translate swedish string:

we {1} had it

i i'd expect:

vi {1} hade det

but, puzzlingly, this:

we {2} had it

returns (notice braces got translated parentheses):

vi (2) hade det

what on earth??