As a person with a less than preferable laptop, I time out alot when playing on realms or servers.
This usually happens when i go through a nether portal, whether im going to the nether or coming back. Recently when this happens and i log back in, i'll be in the dimension i was travelling to, but at the coordinates my portal was at in the other dimension. (eg, nether portal at -17 65 70 in the nether teleports me to -17 65 70 in the overworld, even though my portal is quite far away) This leads me to having to die to get back home, abandoning all my best gear and having to practically start fresh. I hope this helped and the issue will be able to be resolved soon.
Regards, Alex Smith