from what ive learned from others in the very recent past is the kabylake intel Pentium dual core cpu cannot do more than 4 gpus. it is possible its been fixed since but prolly not, it doesn't seem to detect any more than that, skylake g3220 intel Pentium dual core cpu is just fine at doing 6 gpus
I have rigs with g3930 Kaby Lake and haven't had any problems with 6 GPUs