Ender 3 S1 Pro - Hotbed temperature runaway

Ender-3 V3 Printers
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1

Hello everyone!
Looking for assistance with Ender 3 S1 Pro printer here. Before I return the printer which has been working for several months without any issues I want to ask here as a last resort

The issue has started occur recently. During a printing after about an hour of printing the hotbed temperature drops for about 10 degrees without obvious to me reason and then it reports on the screen that Temp. abnorm. after that printer freezes. Sometimes if temperature drop continues for a short period of time (less than a minute) it gets back to the normal. See temperature graph from octoprint

Screenshot 2024-07-19 at 10.39.07 AM
Screenshot 2024-07-19 at 10.39.07 AM1248×1290 140 KB

I checked and re plugged all wires for hotbed disassembled/assembled the hotbed. Nothing helps. All wires look good no signs of burning or something like that. All components are stock nothing added. I have no idea where to look at

2

Thermistor gone bad perhaps? Don’t know if you can change those out individually on that printer or it is a new bed.

3

this is the last last logs from printer just before printer errored out:

Recv: ok
Send: N12303 G1 F1200 X117.408 Y87.436 E150.40301*51
Recv: ok
Send: N12304 G1 X117.498 Y87.053 E150.4161*107
Recv: ok
Send: N12305 G1 X117.612 Y87.36 E150.41861*97
Recv: ok
Send: N12306 G1 X117.734 Y87.69 E150.42772*99
Recv: ok
Send: N12307 G1 X117.786 Y87.827 E150.43259*84
Recv: ok
Send: N12308 G1 X117.817 Y87.922 E150.43592*88
Recv: ok
Send: N12309 G1 X117.94 Y88.464 E150.4544*82
Recv: ok
Send: N12310 G1 X117.952 Y88.549 E150.45726*84
Recv: ok
Send: N12311 G1 X117.992 Y88.963 E150.47109*84
Recv: Error:Thermal Runaway, system stopped! Heater_ID: bed
Changing monitoring state from "Printing" to "Error"