Google Search Console: Indexed, though blocked by robots.txt

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Just noticed this coverage warning in one of the old sites. Search Console is giving warnings on these pages:
/tools/required
/tools/required/captcha?nocache="
/tools/blocks/form/ajax_responder

I've commented out the line in robots.txt:
#Disallow: /tools

Not sure why Google is picking this up in the first place. Is there another way to fix this? I haven't noticed this so far in sites built with new C5 versions. The new C5 also has /tools disallowed in robots.txt:
Disallow: /application/tools

BlueFractals