I could not duplicate it. In a new project, I did a new JSONPARSE, changed the Found Value to Numeric/Bit, it sets it to D1028 (Return Results is D1030):
JSONPARSE SS0 DST511 1 0x100 """Name""" DST511 SS0 SS0 DST511 1 DST511 D1028 D1030
I did a Replace of D1028 with D2000 and it worked:
JSONPARSE SS0 DST511 1 0x100 """Name""" DST511 SS0 SS0 DST511 1 DST511 D2000 D1030
That doesn't mean there isn't an issue, it could just mean I could not duplicate it doing the steps above (e.g. may be a combination of your specific parameters).
Please provide the steps where you can duplicate it in a New project. If you can't duplicate it in a New project, that may point to a different issue (let us know).