I had very often issues with programming bare chips if any other connection is on MOSI/MISO or let’s say on the SPI. I would suggest to check your chips on a breadboard on load the boot loader before using them in a circuit. In your case it looks like you connected your 2.4g Radio as well to the ISP which in my cases always interfered with programming. I solved that by using jumpers to isolate the AVR when programming. Hope this helps preventing you from throwing away chips which might work...

Good luck

Without knowing the circuitry I assume that INA's readings interfere with your PWM. As soon as you're in an off-state current for sure is 0mA in an on-state it is like you said160mA.
You should buffer the readings of your INA with a elec-cap to smooth the voltage over your shunt. But as said this is an assumption. We need your circuit to understand what the cause is.
Hope that helps.