hello:)
I have a LO who did exactly the same at about 6 1/2 months old. I too ended up wondering what to do, until I saw the sub heading '6-9 months - Riding Out the Inconsistencies' in the BW with the text, some days your baby will take a long nap in the morning, sometimes the afternoon, some days will just drop one out! So if your LO is happy when awake, sounds like he's doing what he should.
One thing I found helpful was to extend the awake time in the morning a bit, which usually means a longer morning nap - my LO had just got used to getting sleepy and could actually stay awake longer - I just did 15 mins later per day until the morning nap started at 930.
Hope you figure it out
