In July after a tyre change for the rear of my commuting Moulton APB I used Velocity Veloplugs for the first time instead of rim tape. Those seemed to be okay. Recently I had the front tyre off the bicycle and I put Velocity Veloplugs in that rim, but this led to problems.
I pumped the tyre up and successfully did a few messages on the bicycle. The following morning the front tyre was flat. I took it off and found that one of the Velocity Veloplugs was not where it should be. There was an empty hole, I found the plug loose in the tyre. The tube was punctured at the position of the empty spoke hole. I repaired the tube using quite a big thick square patch, put the Velocity Veloplug in the spoke hole carefully, then started pumping up the tyre. After a short time of pumping the tyre started making a hissing sound and it was obvious the patch had not worked. I took the tyre off and examined the patch in the tube. It was obvious air had been leaking out. I reckoned that as the puncture in the tube was right at the very same place as the Veloplug, the plug was probably pushing the tube puncture open by its shape, after all the Veloplug must indent the tube a bit and that indentation was opening up the puncture. Then the air was able to come out through the opened puncture and work its way out of the patch.
So, I have abandoned using Veloplugs now and for the front wheel of the commuting APB I am now using Velox rim tape. No more Veloplugs for me.