A simple misunderstanding of the issue. A very common (and totally different) issue with regular LED bulb replacements is referred to as "hyperflashing" - the turn signals flash rapidly as if a bulb is burned out. This is what you read about before. Using an LED-spec'd flasher unit or in situations where you can't (flashing controlled by a computer module like in my car) a "load resistor" (typically 6 ohm / 50 watt with a big heat sink) is used to simulate the missing incandescent bulb.
OP's totally different issue is unique to some switchback LED's, which run a bright white in regular running mode but when the turn signals are used, the white portion turns off, and an amber portion blinks - emulating the DRL/signal setups on some late model cars. The aftermarket LED's designed to operate similar to this are called switchbacks. I've installed them in multiple vehicles. Some work well, some do not. They depend on sensing the voltage to determine whether or not the white portion should turn off and when it should come back on. When the voltage is out of range, they don't know what to do...and begin flashing erratically like they're trying to cause seizures.
Switchbacks operating properly in my '06 300C SRT8 for example:
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