This signature first showed up on Nightly in the 20190321104132 build (Android-only). The changeset for that Nightly is: https://hg.mozilla.org/mozilla-central/pushloghtml?fromchange=25398e555020fef80c7b2a06a0d4c667e861cd6f&tochange=b2f1edb41241d3da6ded54edf38cca1d2d08325b I don't know if it is exactly the same issue, but the timing seems suspiciously similar.
Bug 1538237 Comment 9 Edit History
Note: The actual edited comment in the bug view page will always show the original commenter’s name and original timestamp.
This signature first showed up on Nightly in the 20190321104132 build (Android-only). The changeset for that Nightly is: https://hg.mozilla.org/mozilla-central/pushloghtml?fromchange=25398e555020fef80c7b2a06a0d4c667e861cd6f&tochange=b2f1edb41241d3da6ded54edf38cca1d2d08325b I don't know if it is exactly the same issue, but the timing seems suspiciously similar. edit: on the other hand, Android PGO landed in that build, so it could just be a signature change.