By looking at the BPM transmission tool one can see that there is more charge on TL/BP.03 than on TL/BPM.02 (see attached image).

The BPM seetings have been checked and they are similar.

One can see a similar effect when comparing TL/ICT.01 and TL/ICT.02.

Possible interpretation: the beam is scrapping the beam pipe and creating a shower of secondaries.