GE GXRM10G output is higher TDS than input, after replacing all filters -- whaa?

I recently replaced filters and membrane on my GE GXRM10G undersink RO system. After a couple of weeks I checked TDS, expecting product water to show a tenth or so of feed water TDS level, but product water actually measures higher than feed water! Product (output) water is 775 ppm; source water is 660 ppm. And we're seeing a slight green color in the product water that we hadn't seen before. I did the filter job myself, using the correct new GE filters. I'd changed pre and post filters before, but this was the first time I'd changed the membrane, which was at least 6 years old. I was careful, and things seemed to go smoothly, but I guess I could have screwed up somewhere. Thanks in advance for any assistance you can provide.

Make sure that the membrane is seated all of the way into the housing. Water may be getting around the membrane.

Have you flushed a couple of tank-fulls of water? There is a preservative in the membrane that may add TDS that will need to be flushed.

I have not heard of the green water before. I do know that RO water is very aggressive and will try to dissolve anything it may come in contact with. Do you have copper water lines after the RO system?? Copper is well known for corroding with RO water and can turn water green.