Hi,
In the change log, it shows the changes are done in CJ20N.
You have changed the WBS element, but the cost accumulated in the old WBS element based on the network, your screenshot confirms it.
So the PR is account assigned to Network, Go to the PR and check whether this is account assignment to Network or WBS, if network, check in CJ20N to which WBS element it belongs
Regards
Terence