The following line ids are not recognised: rb1x, rb5 (EntityNotFoundException)

Unified API
1

From about last Friday onwards I am seeing the /Line endpoint throw an EntityNotFoundException for the rb1x and rb5 river service. For example try…

https://api.tfl.gov.uk//Line/bakerloo,central,circle,district,dlr,hammersmith-city,jubilee,london-overground,metropolitan,northern,piccadilly,rb1,rb1x,rb2,rb4,rb5,rb6,tram,victoria,waterloo-city,woolwich-ferry/Status/2018-05-06/to/2018-05-07?detail=false

The mode status endpoint returns the above river services no problem, e.g https://api.tfl.gov.uk/Line/Mode/tube,dlr,overground,river-bus,tram/Status?detail=true

Is this a known issue?

Best,
Malcolm