Yes, I've seen that scam shield rarely works for me as well. I'm on TNX so I don't have call screener app anymore just the reported "superior" scam shield, but it doesn't seem to work very well. I get scam texts and calls quite a bit.
Was in San Juan area feb 20 through 23rd for my 41st bday....was amazing and so was tmobile's performance! Great signal everywhere i went while my ATT toting friend was stuck having to use wifi or my phone as a hotspot! Interesting.