Chicken out at night.

I wouldn't worry too much at the moment, just keep an eye on her. I had a hen who went through a long spell of laying thin shelled and / or shell less eggs and it really can take it out of them. As you say, she may have been struggling with the first and then was out of sync for the second.

Keep an eye on her, particularly if she seems out of sorts and with no egg having been laid (this could mean it is still inside her which could possibly turn to peritonitis.

Also make sure she has plenty of oyster shell available. I think some hens are just prone to the thin shell / shell less eggs but it is also possible in these shorter winter days that she could be lacking in vitamin D which helps with calcium absorption. I have heard that a drop of cod liver oil mixed in with their food can help.

How old is your hen?

Also give them access to greens (grass, cabbage) as this helps in the absorbtion of caicium.
As an ex batt she is quite old, probably nearer to 3 than 2 as they lay for 18 months after coming into lay at at least 22 weeks+.
She runs the risk of an egg breaking inside her, so keep an extra eye on her.
BIL warrens lived for about 3-5 years, though not many eggs in last year.

My ex batts have always laid a lot of soft eggs.  When they are having a particularly difficult time laying they often wont go inside and sometimes they feel quite hot, so I'm assuming they feel more comfortable outside in the fresh air (my run is totally covered so fax proof).  However, I always lift them inside as I have the idea of them being left on their own outside.  If it's the summer, though I put them by the coop door and leave it open for them.