One of the most frustrating and mysterious happenings in golf is when you feel you've been making such great progress and all of a sudden, you seem to re-lapse back into old habits. We can find it hard to believe as we are certain that our swing hasn't changed but we find ourselves hitting that dreaded slice or errant shot again. What is actually happening here?
The biggest reason why our swing slowly relapses is due to not paying attention to our fundamentals. The main fundamental that causes the most harm is the alignment. For eg. You might be someone who slices the ball and you've been working on trying to come from the inside on the downswing, however out of nowhere you start slicing again. This may be due to the alignment being too far left of target.
When the body is aimed too far left, it can cause the swing to develop an outside-in swing path. A slice is caused by swinging left too much so if your body is positioned overly to the left, it will exaggerate the problem. This is the same situation if you're hooking the ball as well. Just ensure that when you practice that the body is parallel to the target so to ensure no bad habits are forming. The better your alignment, the better your path will become through default.
The other reason why your swing may re-lapse is just a misunderstanding of what should happen in the swing. You may even be aware of what it should look like but there still might be a gap in how to translate that into the swing. The best recommendation is keep booking in with your coach once a week or every fortnight until you're very clear on how the golf swing functions and more importantly, how to manage your personal habits.
If you need any further help with your swing, please don't hesitate to book in for a lesson.