Playing on EU datacenter but have same issues with twelve99 for over a year now.
Every single day (extremely rare when it doesn't happen) during prime time (6:30pm-11pm) ping jumps from normal ~25 ms up to 120-180 ms.

T-Com ISP

Traceroute:

1 <1 ms <1 ms <1 ms 192.168.1.1
2 5 ms 4 ms 5 ms 172.27.99.1
3 5 ms 5 ms 5 ms 172.24.112.129
4 5 ms 4 ms 5 ms htr11-gut24-3.ip.t-com.hr [195.29.240.173]
5 5 ms 5 ms 5 ms gte01-htr11.ip.t-com.hr [195.29.3.42]
6 100 ms 100 ms 102 ms zgb-b2-link.ip.twelve99.net [62.115.183.214]
7 123 ms 115 ms 102 ms bpt-b6-link.ip.twelve99.net [62.115.122.174]
8 138 ms 135 ms 123 ms win-bb1-link.ip.twelve99.net [62.115.138.202]
9 138 ms 140 ms 142 ms ffm-bb1-link.ip.twelve99.net [62.115.137.202]
10 148 ms * * ffm-b11-link.ip.twelve99.net [62.115.124.117]
11 114 ms 117 ms 119 ms squareenix-ic-369631.ip.twelve99-cust.net [80.239.195.85]
12 145 ms 141 ms 144 ms 80.239.145.241
13 142 ms 147 ms 144 ms 80.239.145.101

Sadly, Telia (twelve99) is SE's provider for EU and they won't do anything about it.