Suffered a similar situation to @tjtrolinger with Web IDE + 0.7.0.rc2.
Had a case where all things looked normal from a development point of view, but out of the blue, updated application on the Web IDE would not actually update a device, even though we see the normal flashing magenta and all that. (Hence my post Web IDE - macro to provide build number? to assist with know what is on the device has been actually updated.)
I could DFU okay to the device, so DFU'd Tinker, then tried OTA again to no avail. Updated public cloud key. Still no go.
Good news is that this thread cured my woes as I took the advice to:
particle flash --serial bootloader-0.6.2-photon.bin
Question now arises - does anyone know what kicks off this condition? Specifically worried about this issue being a problem with devices in the field.