It is super variable, especially for intra-EU and intra-Nordic. I find that longhaul flights post within a few days. The Nordic and Europe flights can take anywhere between 2 days and 2 months. From time to time SK has curves where it seems to take forever for points to post and then there are times they post the next day.
Consistently inconsistent even though my booking email tells me before flying how many points I will earn (ignoring OT upgrades). They could really post the minute the plane touches down or midnight the day of arrival, something other airlines do.