LED problems

Some of the thermal limit systems are designed for 12.7 volts not 13.7

Do your test again. But exact time the shutdowns

Unplug

Wait at least 4 hours or overnight

Retest

Do the bulbs stay lit longer when unplugged?

Then you ID'd yes/no as a thermal issue.

2oldman wrote:
Check voltage.

The bulbs you got might not be the right ones for those fixtures.

Hopefully the old bulbs have a number on them.....and you can look up the spec's and see if they really are 12 V or something higher.

Those fixtures may have a "balast" that increases the voltage for a halogen bulb, just as an example.

When they go OFF, are they HOT to the touch ?

Check voltage.

All four shutting off at the same time? If so the problem is a power issue, not a lamp issue.

bad bulbs, possible improper solder job. Return them to supplier