[exim] Missing curly bracket

Hello,

I have following redirect.

test_redirect:
driver = redirect
domains = gmail.com
local_parts = user
headers_remove = ${if match{$h_Subject:}{\\[SUPPORT\\]}{}{Subject}}
headers_add = ${if match{$h_Subject:}{\\[SUPPORT\\]}{}{Subject: [SUPPORT]
$h_subject:}}
data = recipient@???

Redirect is working in exim-4.82-1.el6
But in exim-4.84-4.el7 i have following error:
R=test_redirect defer (-1): test_redirect router failed to expand "${if
match{$h_Subject:}{\\[SUPPORT\\]}{}{Subject}}": missing } at end of string

Can you please help me what i missed here?

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