Custom tooltips refreshes too slow

Hi,

I have installed the August update of RS server in a dev environment. ALL Custom tooltips refreshes too slow.

Before the reports only 10 s ,now need 40s+.

tooltips by powerbi self just need 2s, other 30s+ for Custom tooltips.

This problem also exists in Google, firefox, IE10, IE11

This is unacceptable to us.

Any suggestions welcome, as in its current form it is unusable in our environment.