+RW disc not recordable in Lite-On 1107

I have 2 recorders, a Panasonic ES15 & Lite-On 1107. My +RW discs have become unrecordable on the LiteOn one by one lately. I tried reformatting them in the Panni. Did not help. Is that formatting causing the problem? What is the remedy?

During the weekend I find a way to revive the +WR disc to record in the LiteOn. I recorded a short title on the Panny. to check if the disc is OK. Then I put the disc in the LiteOn and erase it. After that I was able to record with the LiteOn. I repeated that with another disc and confirmed it true. Problem seem to be solved, but no logic to it.