Blinking occurs with some leds because that's when the cold lamp check is being done at key on. It's happening in the background with tungsten lamps, but you don't see it because tungsten is to slow to show the short test pulse as a flash. If the replacement led was replicating a tungsten lamp it shouldn't flash at all. If it flashes (bright?) then the led lamp cold doesn't look like the near short circuit the cold check expects and the lamp check sees it as an open circuit bulb= FAIL.
I've never understood why everybody uses the semantics 'CANbus compatible'. All lamps whether led or tungsten, have 2 wires. They all get a hot and cold checked the same way. Either a current pulse at key on when cold or the running current is checked when they are hot. CANbus just responds to the result as measured. Therefore the bulb must contain components to suppress or spoof what is monitored by the lamp module so it doesn't send the wrong answer for CAN to then interpret as an error.
True CANbus compatibility might be achieved with an OBDII dongle that intercepts and blocks bulb fail messages, but nobody has made one of those yet. There was a German guy who did some good work on another V.W. He was able to locate module firmware code for lamp testing and modify it. He even wrote an app. with a table of lamps so you could choose which lamps to include or exclude for bulb failure checks.
It's fairly easy to add a few components to a lamp to fool the 'Key on cold' check, but it's more difficult to do it for the hot running current check. Which is why many led lamps are sold with ballast resistors that can get hot, draw the same power, and have to be located in a ventilated space.
If you plug in a replacement led lamp which flashes at key on, the the cold check is still active. It's then down to the lamp internal parts to spoof the cold lamp current or if it's an available option, turn off cold lamp checks with vcds. When I last looked you could turn it off for some but not all lamps. But I would rather keep the fail indications. Small led bulbs are more easily spoofed with a ballast resistor, But this may not work for the cold lamp test because a tungsten lamp appears like a near short circuit for the pulse check. Most of these lamps incorporate a simple capacitor, but there's no guarantee it will work for all car systems using different pulse width durations and number of pulses >1.