Popping on deceleration occurs normally; nothing wrong with it, nor is it an issue or problem.
Earlier model OEM exhaust is 3 chamber, so the popping (that do occur) can't be heard.
Current model OEM exhaust is 2 chamber, producing a (rather nice) deceleration "burble" and the occasional "boof" (a muted pop).
If the popping sound is not the preference, then changing to the current model OEM exhaust may be the middle ground (and cheaper, for a used one). It is not a direct change over; some minor filing, spacer, long bolt, will be required.
Alternatively, a "quieter" aftermarket exhaust (e.g. Yoshimura R77) but they are too expensive new (IMO) relative to what the bike now worth.