My hybrid did the same before she stopped laying, its quite common in younger an older hens. As long as she's getting the right feed and supplements it shouldn't be an issue
You might look through these and see if you can match it. It's not unusual for a hen to occasionally lay a weird egg, we are all entitled to an occasional oops. Sometimes it can be genetic or some other explanation though, especially if it happens regularly.
When I see problems I try to decide if it is a flock problem or an individual hen problem before I decide on an action. If it is just one hen doing this then you probably don't have to worry about flock-wide problems like a disease. I don't want you to get too over-concerned on some of the stuff you might read on those links.