Those light 'things' spanning the girdle are growth from camibial cells that you missed when you made the girdle. You can easily remove them and clear the girdle. Then soak a piece of paper towel in isopropyl (aka rubbing) alcohol and thoroughly wipe down the girdle (to the point of scrubbing) to make sure that all the cambial cells in the girdle are G O N E.
You could do all this now, but it is not clear if you will get enough roots so that the layer can be harvested and the roots hardened in a pot before winter. You can leave everything in place through the winter and the process with automatically restart next season, even if winter kills all the roots formed this season (it won't matter because the layer is still on the tree whereas separated and in a pot it will be dead).
My experience is that using bonsai medium instead of sphagnum works better, especially for over-winter layers. Since you have a more or less vertical stem, I suggest that you cut a plastic pot down one side and half-way across the bottom. Cut out an area to accomodate the stem in the bottom of the pot. You will then fit this around the stem. I put two or three long screws into the stem below the pot to support it, but you can support the pot however you wish (obviously) - guy wires from branches above, for example.
Then you place a little bit of damp sphagnum in the bottom of the pot (around the stem and in the drain holes) before you pour in you favorite bonsai medium (mine is Turface MVP). If you are willing to water this regularly, you are done.
If regular watering is going to be a problem, the whole works can usually be easily sealed in plastic when the pot is supported by screws. In some awkward circumstances I have used a (gallon or larger) plastic bag instead of the pot. With a bag one has to work a bit to tape up the split on the side of the bag whereas with a split pot you just need to thread a bit of wire through a couple of holes (one on each side of the slit) and twist to close up the split pot.
With the traditional sphagnum-in-a-bag method one gets thick, fleshy, white roots that are very fragile. They need something like 6 weeks after harvesting to grow in a bonsai medium to harden, whereas with the split-pot-of-medium methods root hardening happens simultaneously with layer root growth. This will usually will save an entire season when one doesn't run into a problem like you have. In your situation it means better root survival over the winter AND, since it is effectively alrealdy potted, you can harvest, whenever - it is already potted!
The disadvantage of the split-pot method is that it is more difficult to see how things are going. Often the screws can be removed to allow the pot to be slid down the stem. You likely won't be able to do this on a Suiju. I gently work the medium with my finger near the edge of the pot. The medium is very loose when it is unpopulated, whereas it gets firm when bound up by roots. I'm sure you can figure it out - the point is to do this at the edge of the pot instead of at the stem where one risk breaking off newly formed roots.
BTW, I think Suiju is well worth the trouble to layer.
Best wishes.
Now, back to the Boda box
In my case, I should have re-wounded, re-applied hormone and continued on, as this has worked for me in the past. Now I just have a dead top. This tree is much nicer than mine, and I would be very eager to get it rooted. If the callous does not bridge, and it does not root, it will die(*eventually). I looks like the callous has not bridged on yours so I say press on. In any case, keep it wrapped and damp as this should speed callous development. good luck
