Sorry for the late replies. This is not about web extensions.
I believe I figured out why this was happening. Since I have the current (non-development) build of my extension on my development machine, I always disable the extension before testing. When I test new builds, I test in Safari and a fresh instance of Safari is initialized, which has my non-development extension disabled.
That means every time I re-build, I have to re-enable the extension. If I do not disable the extension before building development versions, I seem not to encounter this.
It all sounds rather long winded and confusing, but since realizing this, I haven't encountered the issue, so far.
Topic:
Safari & Web
SubTopic:
General
Tags: