send_command() uses multiple write() operations to send the sentence and the GPS might not recognize the sentence if there is a delay in between the write operations.
Each send_command should produce one PMTK001 message and an absent message indicates that the command was not recieved.
The code below may or may not output 4 PMTK001 messages after a soft reboot on an Feather M4 Express with an attached GPS breakout.
Also, the GPS keeps sending the additional messages if the third PMTK314 is not received.

Combining the writes into a single one helps.

`
import board, busio, adafruit_gps
uart = busio.UART(board.TX, board.RX, baudrate=9600, timeout=3)
gps = adafruit_gps.GPS(uart, debug=True)

gps.update()
gps.send_command(b'PMTK314,-1')
gps.update()
gps.send_command(b'PMTK314,1,1,1,1,1,1,0,0,0,0,0,0,0,0,0,0,0')
gps.update()
gps.send_command(b'PMTK314,0,1,0,1,0,0,0,0,0,0,0,0,0,0,0,0,0')
gps.update()
gps.send_command(b'PMTK220,1000')

for i in range(20):
gps.update()
`