strange RFM95 SPI behaviour with STM32L4
I did not manually reset (pull pin 6 low) the RFM before performing the above operations. I simply relied on the device resetting after power was applied. Page 108 in the datasheet indicates that the chip requires a 10ms wait after a reset is issued on pin 6. I decided to implement a manual reset at startup, and wait 10ms. SPI communication worked as it should thereafter. Power is not always cycled while programming, so the manual reset is necessary.