We're seeing issues with routes traversing NTT. Specifically routes that go through ae-*.r23.londen03.uk.bb.gin.ntt.net.
This isn't majorly impacting service but will show as packet loss within the quality monitor, although the line is unlikely to have any actual packet loss itself.
NTT have been contacted and we are awaiting a response.
Edit: NTT confirm r23 isn't working as well as they would hope and are investigating but cannot provide an ETR at this time.