HI folks! I come seeking en"light"enment and, if I'm really lucky, a simple cheap solution.

So I have a lot of plants in my home. Some I grow on a light stand lit by two side-by-side 2-tube 4ft shop lights on the top level and the same on the 2nd level. For decades I used fluorescent tubes. But over the last maybe 5 yrs, I have been switching them over to LED. Several of the fixtures are old, but servicable, and I don't need anything fancy or costly. A couple of them, because of their age, when the old fluor. tubes had died and I was switching over to LED, I removed the ballasts. (Figured it was likely only a matter of time before those died, too.) A couple I did about 3yrs ago, turned out well. No issues. But...

This past week, as the last of my fluor. tubes bit the dust, I decided to change the last fixture to a no-ballast LED. Removed the ballast and rewired as usual (all wires from end #1 of the fixture attached to one of the power cord's wires, and all the wires from end #2 going to the power cord's other wire & the grounding wire left untouched). So power in one end of the tube and out the other.

Here's the part that baffles me. When the LED tube is inserted into the tombstones on one side of the fixture, it lights up perfectly. When I tried the tombstones on the other side, the LED would not light up at all. I figured, "Okay, the tombstones in this fixture are old. Those two just need replaced." And so I did. Here's the weird part. When I then inserted the LED tube into the new tombstones, it lit up BUT will only do so if I install the tube upside-down. If I try to rotate the tube in the sockets 180 degrees or take it out and install it the way it is supposed to be, it will not light up at all. (Switching the LED bulbs, as expected, makes no difference.)

Thoughts?