I noticed in a few situations where I complete an event such as a mystery and the reward are 2 skill points. If I don't use them right away and say I do other missions or proceed with acquiring a wealth treasure chest or do other artifact or mystery event, at some point, my skill points disappear.
This happened in particular when I completed the legendary wolf event, think it was called creeper something. Took awhile to kill the 3 big wolfs. I earned my two skill points. I didn't use them right away, proceeded with doing another event, don't remember which, and then when I went back to my skill tree to use the skill points, they were gone. This happened with the new patch on v1.1.2. However, I noticed similar behavior in the prior patch of v1.1.1 with other events that provided skill points.
Issue happened to on v1.1.1 about 2 or 3 times where the skill points disappeared if I didn't use them right away. On v1.1.2, happened once so far after completing the legendary wolf event, creeper something.