:mkview followed by :loadview makes a buffer tab disappear

[tmandry]

If I have multiple buffer tabs open, sometimes :mkview followed by :loadview makes one or more tabs (not the current one) disappear.

It seems to matter which buffer is active - doing this in a particular buffer might make two buffers in the same window disappear. But doing it in one of those buffers doesn't make any buffers disappear.

I've tracked it down to the command :doautoall SessionLoadPost at the end of a view script (running only that triggers the behavior). However, calling all the functions listed in :autocmd SessionLoadPost does not trigger the behavior. Also, I looked at the session string before triggering and it looks correct.

I'm using g:wintabs_display = 'statusline' and vim-wintabs-powerline.