Caching problem when trying to submit a change whose dependent parent change has been merged

Steps:
1) Change A that modifies line X
2) Change B depends on Change A, also modifies line X
3) +2 and sanity +1 both changes
4) If you look at Change B, it says "Merge conflict".
5) Press submit on A to merge.
6) Refresh page of Change B, see "Active", and "Submit" button is grayed out with "Problems with integrating this change" hover text
7) Hard-refresh (using developer tools) page, "active" changes to "can be merged" and Submit button becomes blue.