I am no expert, but I would replace the flasher relay first. There use to be a small 'can' you would 1/4 twist out, and replace, when this happened on older cars. Not for sure how it works now, but way back when, the flasher circuit consisted of a capacitor and a resistor, the R/C network created a charge / discharge circuit, which make the light blink. I have to think this has been far improved since this 'olden time' but I'll place my bet on the flasher relay.
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