Shaper guardian maps dont drop t17s

As the title suggests.

I have run this weeked around 30 shaper maps and at some point I started wondering where are all the t17 maps. Started tracking it and noticed that even "normal" map drops that were dropping were off-atlas meaning that they did not respect my watchstones at all. Ended up having dozens of low tier maps for my kalguuran merchanaries.

Not sure if this is intentional or a bug but this greatly devalues the shaper maps in general when you can't get good maps out of them.

Edit: After 2 days of shaper guardian mapping finally found a fortress map. Maybe it's because when "adjacent" map drops random t1-15 it can't convert. Making them twice unlikely for them to show up. (assuming 1-2 adjacent drops per map and 1-2 normal drop random maps).

Not sure that this adjacent dropping low tier maps is intented or not