wixData modifying JSON order on save

I’m saving a JSON object to an Object field in my collection, but the saved object ends up being formatted differently.

The object is a calendar, so the top level consists of keys for each month. The object before save is in the correct order (Jan, Feb, Mar etc.) but the saved version is jumbled with no discernable pattern (July, Jan, Aug etc.).

Each object is fairly large at around 200KB.

The items within each Month have remained correct, but they follow a numerical order.

Any ideas what could be causing this, or a way to fix it? It’s no big deal to re-order on retrieval, but it seems like a possible bug within .save().