I am getting these spikes randomly during the run and sometimes during immobilization. I am attaching an image of a spike during the kinetic run. it is not specific to a particular interaction... it is very random. i am using Biacore T100 and the system is well maintained with Desorb and sanitize and only desorb as per recommendation
What you see is probably an air spike although it should not happen within a T100. I trust you filter your buffers to get out small particles like dust. You can degass the buffer yourself and look if there are less spikes.
Maybe the injection port needs cleaning (look in the book).