Yes, I also don’t know. Anubodha is quite commonly used in the simple sense of “understand, wake up to”, as for example:
There are other principles—deep, hard to see, hard to understand (duranubodha), peaceful, sublime, beyond the scope of reason, subtle, comprehensible to the astute—which the Realized One makes known after realizing them with his own insight.
It doesn’t mean “discover” in the sense of being the first person to find out about something.
No, here bodhi is not the noun “awakening”, but the aorist first person singular, “I awakened” or “I understood”, i.e. “I awakened to bliss”, or less literally “I understood the true meaning of happiness”.
I don’t know if it’s firmly established enough as a technical term to draw definitive conclusions. In this context, it seems to mean becoming a Buddha. However, at MN 95 it is described as stream-entry:
Persevering, they directly realize the ultimate truth, and see it with penetrating wisdom. That’s how the awakening to truth is defined, Bhāradvāja. I describe the awakening to truth as defined in this way. But this is not yet the arrival at the truth.”