It would be great to be able to assign transfer into an account as a category i.e. if someone transfers money for a meal, then it would cancel out some of the spending done under that category
This has been an issue since the beginning of Monzo. Hopefully one day they’ll fix it, especially now they’ve beefed up the budgeting as part of plus, it leaves a bit of a hole in the numbers, especially if you use both your solo and joint accounts 
I only noticed it when I went to export my statement to Google sheets, definitely missing it