Formal email to explain to students a grading mistake.

I'm writing an email to my students explaining my mistake about their grades. Please help proofread the draft. I really need your help. For your context, there are 5 sections submitting assignments on one website. There are 5 TAs corresponding to the sections. Any TA can publish the grades, and those grades should be of all sections.

I just wanted to let you know that your grades for experiment 2 post-lab have been posted (again). Some of you must have seen your post-lab grades last week and then found that they disappeared. That was a mistake and I apologize for that. What happened was I took the first glance and graded a few of your post-labs, but meant to go back to adjust it. Unfortunately, another TA in the Thursday morning sections finished grading her section and wanted to publish such grades, making your grades also published, so I unpublished them last Friday. Now that I was able to spend more time and thought on your post-labs, I had your grades finalized and republished them.
Overall you all followed the rubric and did pretty well. Generally, nearly all of you met the expectation, you may get different points between 16 and 20 based on your level of detail, articulation and clarity in writing. This could be your first abstract and conclusion to some of you. I'm sure as you write more lab reports and get to read more scientific articles in the future, you will develop a skill on how to write a good abstract and conclusion.

Hope you enjoy the warm weather outside.