Well no-one has complimented you on a job well done yet so I do. Its a lot of work to make the clips and boards and make them run as well . Thats a CNC machine is it . Did you make that yourself too?Well done anyway . Its very satisfying personally to achieve such resultsI will be trying to get time to try such before next Xmas.
Reading elsewhere I noticed that an 8 meter stip was acting irrationally . The poster found that a suggestion to also power the strip in the middle and at the other end fixed the problem. I wondered if your problem might also relate to the voltage and current supplied?