Thanks for confirming it's being looked into!
For anyone in a similar situation, until this is resolved you can enable cheats and teleport to a different spot on the map, then just save and disable cheats again.:
Ctrl + left click: Holding Ctrl while you left click teleports you anywhere on the map you wish to go.
The enemy army in question didn't pursue me after I had jumped.
Not sure if it would work if you were besieging a settlement but if it's just an encounter in the open it works great.