Based on your analysis is sounds like the issue is with warmed up buffer pool which should then be presented even in Percona-Server. Can you try your test-case on PS and if reproduced there then PS team can look at it and fix it in PS code directly. PXC will inherit the fix.
Based on your analysis is sounds like the issue is with warmed up buffer pool which should then be presented even in Percona-Server. Can you try your test-case on PS and if reproduced there then PS team can look at it and fix it in PS code directly. PXC will inherit the fix.