OK, you're located near the left coast where that kind of construction is common. Unfortunately there is no approved method for tiling over a floor that has framing wider than 24" oc. However we know it works as many thousands of floor are tiled successfully every year out there.
I've even heard of success with 48-50" o.c. where yours is 32". So, lets assume the framing is good enough. Now let's talk subfloor sheets. You have a single 1 1/8"?
TILE GUY - retired- TROY, MI - Method & Product suitability consulting.
I also did a little digging to find there is thinset underneath the Hardiebacker. Most of the backer board is secured with staples with some scattered screws that project slightly.
As near as I can tell the backer board is pretty secure with the exception of having no fiberglass tape at the joints. Even given that there is nothing to suggest why virtually all of the thinset had adhesion problems on both the tile and the backer board.