I suppose you're saying that you are tilting the pot?
4 hours full Sun, is a good increase over 2. Hopefully 6 or more is available in the future.
Honestly I can't answer your question in entirety, but it does happen that a juniper can die
and look green for some time. That it not the case here I'm sure, just unhappy roots and adjusting to a 3rd environment
in a short period which is yet changing to increase Sunlight and watering schedule.
So yes, the tree will not stop throwing yellowing needles suddenly upon corrective action, and I still think next year
you're going to have to do some thinning in Summer, after it takes off with growth splurge mid Spring.
If there was any root rot, and I hate to even mention that because repotting should happen if that ever were the case
and I am not overly experienced with treatments for it because I water correctly best I can for my schedule.
Root rot would have a smell, should sport some little gnats, and black roots somewhere. I would like to defer your
question to
@Brian Van Fleet and get his input on this. He is much more experienced with shimpaku than I am.
BTW evening time is not the best time to water. You're treating with a fungicide, and evening waterings is favorable for disease
when carried out as the normal schedule. Sure nature rains at night, but not as a routine really. It happens, and we allow dry time
soon as possible. It will take time for you juniper to respond favorably to a change for the good. Consider it lag time, catch up.
However you don't have much of a growing season left this year.