Hostile relations not anulled by war

Support ID 6B7683AA

April 9 of YR3 (my kingdom) captured 26 acres of land from (opponent a)

This was the last hostile action by my kingdom. After this point we went to war with another kingdom (opponent b). We were totaling 77 points hostility against (opponent a) at this point.
We proceeded to get stomped by (opponent b) in war. Then as soon as we come out of EOW CF with (opponent b)....

July 16 of YR4 (opponent a) has declared WAR with our kingdom!

There were no further actions by us against them and 10 days had passed.

From the guide.
Immediate Effects of WAR are:

-> annul Hostile Meter with everybody. This overrides Unfriendly and Hostile relations with all other kingdoms to Normal.

Even assuming that didn't happen, with the 16% decay rate the remaining hostile points should only be 13.46 or so. Not enough to declare.

From what i can see this is a bug, and one which is costing my kingdom dearly.

War overrides relations, it does not set them to 0. I can double check that relations decay as normal in war, but it could be that you had your meter incorrect.