Things are starting to get interesting.
The LED chip in the FFL350RD is identical to the chip in the LatticePower TN3535 6500K 70 CRI (test here).
The LEDs differ significantly in their general design (substrate, traces), but there is a certain connection. It would be interesting to know who manufactures these chips. In the case of the circular chips, Sanan was suspected, but what about the rectangular chips?
Does someone know who the biggest chinese LED chip manufacturers are? I suspect that companies like Lumenpioneer only buy LED chips on a large scale and solder them onto their own substrates and (at the customer’s request) add their own phosphor mixture.