Durch revolting and ageing to 5 in 40 min Treaty

so yesterday i played vs someone with dutch. He was revolting and i thought what a troll until 40 minutes ended and he had imperial upgrades on his units. His age up to 5 AFTER he revolted was never shown in the chat.

he was saving all his shipments until he revolted.

while he revolted he had age 5 in queue already

when the revolt was done, age 5 was starting to develop

so in the end he had all the eco from his revolt (south africa) and still all imperial upgrades from age 5

is that intended or is that a cheat?

https://ibb.co/nQbWxxf screenshots