In my opinion it is not real good if it is consistent. If it occurs occasionally I would not worry about it. If they are just starting to lay I would not worry about it.
Their internal egg laying factory is set up to release one yolk at a time and for that egg to take about 25 hours on average to work its way all through their internal egg laying factory. The next yolk is released to start its journey about the time the first one is laid. It is not exact. Some release that second yolk about the same time each day and some seem to wait until the first egg is laid.
Sometimes their internal egg laying factory messes up. This is not at all unusual in pullets just starting to lay. They have not completely debugged their egg laying hardware or software. Sometimes it can happen to an older hen. When they release two yolks closer together, you might get a double yolker. If there is more time between the release, you get two eggs in one day. Usually, if they lay two eggs in one day, the shell gland does not have enough time to prepare enough shell material for the second egg so it is often soft shelled or thin shelled. When they lay double-yolked eggs or two eggs in one day, they usually skip laying the next day.
Different things can cause this in an older hen. Sometimes their internal egg laying factory never gets the kinks worked out of it. Stress can cause problems. I think too much light can cause this. Not sure on that one. My memory is not always the best. If the hen is getting too much protein, she can release too many yolks.
If this is a rare occurrence, don't worry about it. If it is an older hen and is consistent, there may be something there.
Good luck.