Hi @oluwatobi,
After looking at your demux there is definitely something going wrong with how the pacbio sequences are being imported. I found this (old but still helpful) post about pac bio encoding regarding what is happening with your quality scores.
I have created an issue with our development team to get this problem addressed but until it is fixed there is not much to do inside the qiime2 ecosystem but wait. I wish I had better news but hopefully it gets fixed soon!
If you are comfortable with trying some third party options I found this forum post regarding a work around for this. Keep in mind you will not have provenance for this step.
I hope this is helpful!
--Hannah