Final map boss - synthesis map drop

Hello,

i have an issue(or possible bug) with synthesis map drops from final map bosses.

I will try to give as much detail as i can to this issue:

What do i want ? whats not working ?
I want to clear out any map and get some synthesis map drops from the final boss/bosses, but very rarely do once i fill my map device with scarabs and select a map crafting option from my map device.

Atlas tree and setup:

https://poeplanner.com/a/9yR

Map T14+

Anarchy Scarab 2x
https://www.poewiki.net/wiki/Anarchy_Scarab

Anarchy Scarab of Gigantification 2x
https://www.poewiki.net/wiki/Anarchy_Scarab_of_Gigantification

Titanic Scarab of Treasures
https://www.poewiki.net/wiki/Titanic_Scarab_of_Treasures

Map craft: Anarchy


Clarification and numbers:

My understanding is that the chances of me getting a synthesis map from the final boss is fixed at 4% ( 2% base + 2% from Vivid Memories https://www.poewiki.net/wiki/Vivid_Memories ) and no matter how much quantity i have in my maps will change that.
Now those 4% don't sound like much but i can assure you that me not getting those maps has nothing to do with luck.

Sample size and variations:

All the maps are T14+, Alch'n'go and had the same number of total bosses.

50 maps - scarabs(as above) and anarchy map craft ---> 2 synthesis map drops
50 maps - no scarab no map craft ---> 21 synthesis map drops

Those 21 synthesis map drops match up with Conqueror map drops(which are also 4%)
In all the maps i played i get about the same number of Elder,Shaper and Conqueror maps regardless of scarabs and/or map craft.

I hope that is enough to go on