[Bug Report] records missing & cached in new feature Statistics (v4.12.2)

[15921483570]

Description

1. upload a problem with 2 or more stds
2. open the problem, then notice the row just below the title, Tried: 0. but after clicking Tried: 0, all the stds' records should be shown.
3. return to the problem, open Statistics from right panel, and only one record in the Submission Statistics would be seen.
4. delete the problem and repeat the steps before several times.
5. open Statistics from right panel, and several records in the Submission Statistics would be seen. The records are the new one with every past record occurred on the problem's upload, and, of course, should be disappear simultaneously
   on the problem's deletion.

Here's the problem

B0-Hello world.zip