Why are my LED bulbs pulsing/flashing?
Try adding a single halogen along with a few LED's, and see if that fixes things. If it does you probably do actually have a dimmer, you just don't know it. Or the power supply doesn't understand the load and keeps switching itself on and off.

And note this:


  CAUTION: Recommended for use with 50-60Hz AC magnetic transformers or regulated DC power supplies/drivers only. Not recommended for use with high-frequency electronic AC transformers, as this usage will either create non-functional lighting, or if functionality occurs initially then internal MR16 LED bulb damage may result in premature product failures. Use of high-frequency transformers will void the warranty.


I suspect this is what is happening to you - the transformer is actually making high frequency A/C mixed inside low frequency A/C. And the LED power supply can not handle it. And/Or the transformer doesn't understand the LED load and keeps switching itself on and off.

This page explains it better. (It's too much text to copy into here.)

Your choices are finding a different LED (the page lists an option), or bighting the bullet and changing the transformer. Or switching to regular 120V power lines.