BM 1.10 Militia Bug

In fresh BM 1.10 game AI colonized planet just near my homeworld, so i invaded it with around 40 troops.
It had no troops in cargo.
When combat started, there were 300 spartams, ehm enemy troops. So they defeated my invasion attempt. (i destroyed around 40 of their troops)

I of course can build multiple troop transports and full them, with troops, but all of that for one FRESH colony? And give it time to build defenses/be vulnerable to attack when building invasion fleet?
btw. If i could colonize this planet, i would simply glass it, one frigate is enough.

2 build turns for glassing, and around 20 for invasion is realy bad.