I have an ESP32 system  publishing via Http to MySql and  web as per your tutorial.  Mostly everything works fine including a variety of sensor data.  The Serial2 port is connected with a converter MAX232 to a DGT industrial load cell which returns it’s standard weight message on receiving a Read instruction from the ESP. The code runs a Finite State Machine which monitors the various states of a process.  The ESP publishes every 15 minutes or on each change of system state. 
However, after about 30 to 40 minutes the data from the Load cells degrades such that it becomes unintelligible, with missing and spurious characters which my code cannot parse.  I have checked and rewired and fitted RF chokes and ferrite  beads. I have upgraded the PSU to an industrial version as I had suspected noise from the home charger PSU.  The Serial2 is configured at 9600 baud rate. 8None1
I have read that wifi can affect both Serial1 and Serial2 on the ESP32.  Has anyone experienced issues with serial communications and what have you done to fix it? Any ideas why the data reads fine for a while before degrading?  Am I right in assuming it has to be a hardware issue, or could my code be at fault.