Naps suddenly falling apart- 8 weeks

[Cvbaby2014]

My Lo was falling asleep for some naps independently and napping 1-2 hours. 
This is has fallen apart over the last couple of days and is napping 40 mins max if at all.  He wakes within 5-10 mins of being in the crib even though he was able to fall back asleep before.

His awake time is a max of 60 mins but with these short naps I'm trying a longer windows and shorter awake time.
Although currently I'm holding him to sleep as I want him to get at least half an hour!

Not sure why the sudden change,  I thought overtiredness caused it the first day but today, given his first nap was actually quite good I didn't think the rest of the day would fall apart as it has.

[Martini~]

I would kindly advise pushing A times. In first weeks after every wonder week A times usually goes up much. My LO (11 wo) is currently on 2h and strated doing that around 7/8 weeks. From 6/7 months I was having catnaps so pushed him to 3 naps. You can still go on 4 but accept that first or second one is a catnap, push for normal A time and the next nap can be better:)!