Strange effect of a level shifter between Atmega (3.3v) <=> SIM900 (2.8v)

Using Arduino General Electronics
2

Yes tp2 connects to the output of a ''245, If it is high you are potentially damaging the '245 by shorting tp2 to ground. If you NEED to pull PT2 down add a series resistor between the gate and TP2 470R should be within device limits

Bob