SIM7600CE-T 'Garbled' received messages

I'm having issues in the accuracy of SMS messages received. Quite often either the wrong characters are read/found or character mystery marks are displayed. Below is a example of my testing. I have changed some of the phone number numbers because I don't want to post my phone number. This is only a issue with receiving text messages and initialization.

+CMT: #+4420408320a9","","22/12/19,10:57:40+52"
Testing 123

+CMT: "+442040832019","","22/12/19,10:57:57+52"
TESVING 321

+CMT: "+462040832019"\"","22/12/18,10:58:09+51"
123 testing

+CMT: "+442040832019","",B22/12/19,10:58:25+52"
321 TESTING

)CMT: "+442040832019","","22/12O19,10:58:45+52"
TESTING 567

As seen characters are randomly 'garbled' in the date, system characters displayed and messages. I don't get this problem with the SIM900 chip, and I've tried multiple methods of programming using two SIM7600CE-T 4G(LTE) controllers to insure its not just a outlier in hardware. The programming for this test displayed is the example code provided in the tutorial using a 115200 baud rate. My conclusions are that this is either caused from some strange serial communication problem, maybe the aerial isn't the right size (using the aerial provided with the chip), maybe the cellular frequency's are incompatible in New Zealand on 900Mhz and 1800Mhz, or the SIM7600CE-T 4G(LTE) chips are just not accurate in cellular communication. I would like to know the cause of this problem and how to fix it.

DF tutorial: https://wiki.dfrobot.com/SIM7600CE-T_4G(LTE)_Shield_V1.0_SKU_TEL0124#target_5

Thanks for the help!