Hi,
The problem I see is not the transformer, but the PCB is not made according EMI/EMC and ESD standards.
Nowadays circuits are used nearby HF sources like cellular phones, WiFi, Bluetooth...thus - because of lack of a GND plane - all traces will act as transmitting and receiving antennas.
Then there is a connector where directly microcontroller signals are wired to. I see no ESD protection nor HF filters.
Let's imagine the transformer as a car with thieves (HF noise) close to your house. But your PCB (house) circuit is an "invitation" for thieves with open doors (no protection).
Klaus
Btw: since decades computers usually have a "screenshot button" no need to take photos with bad quality and big file size.