Mystery foam from highlighter fluid

I was extracting the dye (which I thought to be pyranine) from yellow highlighters. I have done this before using a different brand and so figured all would be well. but when NaOH was added to solution to observe the colour change, the dye went orange (pyranine turns blue) and this strange foam precipitated out. I now doubt that my dye is pyranine and think it may be fluorescein based off colour. I was hoping someone could help me identify what this foam is, the only other thing I added to the solution was HCL as I forgot which way I had to change the PH for colour change.