Shield Cool-down Effect on 2-3* Transitioner

Unknown

As a 2-3* transitioning player one of the most important ways I can build a 3* roster is to place in the top 100 PvP.
Since the implementation of cool downs for shields this has not been possible.

1-3 hours before the end of the event I shield, for the each PvP I have been rank 74-87 before shielding.
In each PvP I have then fallen to 100+ rank between shielding and the end of the event. Different ending time for each PvP event.
I suspect this is due to an insane amount of last second grinding brought on by the way shield cool downs work.

This means at this time for PvP there is no 2-3* transition possible for me. I somehow suspect this was not the desired outcome of shield cool downs.