LED brake light bulbs

I installed 2 LED brake light bulbs after the local PD pulled me over and told me my brake lights were too dim due to me having smoked tail lights. I checked the brightness after installation and the 2 standard bulds that I didn't replace were actually brighter than before. Now when I use my turn signal, they blink real fast and almost look like (sesquential). Is this normal or because I just replaced the 2 inside bulbs with LEDs?

Thanks

1994 Mustang GT