I've even had issues after removing the veneer tape. After it look like it is completely removed, I'll dye the workpiece and then evidence of the tape adhesive reappears. I think it is the same issue as discussed before. The glue from the tape gets caught in the pores and you need to sand again and again. The problem, of course, is that you may sand all the way through the veneer.
This stopped the veneer tape issues and considerably reduced the glue bleed-through, but some areas continued to appear. My second step is to soak up glue if it occurs. I lay sheets of brown masking paper between the veneer and the caul. This soaks up the glue to the veneer surface. When bleed-through is evident, light sanding is more successful because minimal glue remains in the pores.
With my glue bleed-through issues, I was originally thinking that this would be my last project with sepele. I'm please that this glue-up approach seems to be working so I can use sepele without worries next time.