Branched todos section may appear multiple times when reloading too quickly

Hello,

When reloading the buffer while the main TODOs list has not been populated yet, the branched section will appear multiple times.

To reproduce on this repo, branch out of master, add a todo anywhere in the code, run `magit-status` then hold `G` for a couple of seconds.

This is what happens :

I have not yet been able to identify why this happens, maybe it is a known issue.