We should close this (as FIXED, by bug 1650214), and the new case is best spun out as a new bug--as you've done--even though it's similar. I'll add a whiteboard note that this should stay hidden while that other bug is.
Bug 1741869 Comment 26 Edit History
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We should close this as FIXED, by bug 1650214. Otherwise this will get missed as a security fix in the relevant releases. The new case is best spun out as a new bug--as you've done. Since the original testcase remains fixed we've definitely got an improvement here, even if the new similar stack hints that it may not be complete. I'll add a whiteboard note that this should stay hidden while that other bug is.