There are many components which have hidden pins. One of them is I2C/UART/SPI
I've discovered, that these pins are predefined appropriately to schematic, And Tx pin is configured, as output.
For me it's logic and makes sense that pins are configured during component start, and unconfigured during stop.
Because I wanted to have different output pin configuration for this component, "windows-schematic style" programming damaged 2 external circuits, until I realized what's going on.
I was working before on nrf51 and can't get used to assumptions during programming, which I haven't done, can't change, and not aware of
