Thank you all answering so qickly.
I have tried 2 identical boards and one onether for which I have series of LovyanGFX project versions.
All of the project versions worked nicely this morning and then bang!! and none of them works. Compiling goes still without any issues.
Only libraries installed are LovyanGFX, LVGL and ArduinoJson. nothing else.
For board Arduino AVR boards which is default, I think. And esp32 by Espressif.
Board uses ESP32 S3 Wroom-1.
Only error is : Guru Meditation Error: Core 1 panic'ed (StoreProhibited). Exception was unhandled.
Code runs until calling LovyanGFX xyz.begin()
I underline everything worked perfectly weeks and the suddenly, not.
=> and after remove LovyanGFX from Arduino and copying same version (latest) from git. No improvement. Same fault still.
ptillisch, you were right about that traffic was local but still, 20MB/s is quite much. I wonder why is that. Anyways compilation takes several minues even though CPU is pretty fast. Any ways this slowness is just minor thing.