A customer of mine found a bug related to MyBB and Microsoft Edge browser:
The forum works and looks the best using this browser aside from one issue. When sending a PM message, it seems to submit twice and MyBB gives a warning about sending identical messages too quickly. It happens every time I send a PM.
After some digging, we were able to replicate the issue on Windows 10 using Microsoft Edge browser. Unfortunately, it’s something that affects the default mybb that ships with the most recent release as of this post: 1.8.6.
It’s been reported & confirmed over at the official mybb forums by Jones H, a MyBB staffer and forum owners.
What’s the current fix? Short of using a different browser: none. Once we catch wind of a fix we’ll let our customers know.
Is this affecting you? Let us know in the comments below.