Problems with L3+ Antminer yesterday and today?

Heya,

i am kinda new to the Mining Business, running 1 Antminer L3+ as test right now, starting on Friday with an avg. of 510 mh/s on your side, miner only lists 504mh/s, 98-100% avg. mining efficiency.

Saturday worked kinda OK, still less then i expected (0,965 ltc)
Sunday started to get worse, avg. mining efficency of 80-90% (only 0.813 ltc)
and today i have an avg. mining efficency of 66,67% right now, earning will be even lesser then Sunday and i get rejected Shares:
Both primary and merge mined shares are stale 20

any idea what is wrong? Antminer L3+ tells me everything is OK, 504mh/s mining power.

if i check Hashrate history i have crazy spikes up to 1,8gh/s but also drops to 0 mh/s.....

i am thankfull for any ideas, kinda happy with prohashing.com up to now

They are updating the mining server, they are working on it now to fix and hope we get refunded the losses