Map Drop Rate in Standard League

Hellow, I've been having a serious problem with map drop rate in the standard league. For some reasons it's very rare, I mean almost 'zero', to find high-tier maps (14~16) drop these days.

I've tried every possible thing to get them, but nothing happened. It's so strange. It's like to see map drop rate hit the bottom. My atlas progression is almost over, but whit that and with highly modified maps I still can't find any higher maps drop.

What's going on????

bad luck streak

Nothing has changed besides the Zana mods.

How are you rolling your maps and what else are you using to get more map returns?