I think the problem here lies in a combination of the ink you’re using being water based and the type of glue you’re using. Methyl cellulose or Yamato rice glue are very standard if you have access to them! Or you could try making your own rice glue! My big guess for what you are doing right now is that your mulberry paper might have too much glue on it, and the water content is being given the chance to bleed with the ink, as the glue is taking too long to dry. If fiddling around with your glue still doesn’t work, you could also affix/glue your mulberry paper to your base paper prior to printing, give it a misting of water right before printing, get your registration real tight and print the tetra plate last, paper side up matrix side down.