If you connect two libraries, then debugging does not work?

I add two class libraries to the "solution".
I am running debugging.
Chrome starts up.
In Chrome, the start page `\Home\Index.cshtml` appears.
After `~10` seconds, debugging automatically stops.

Description.
I created a project - `WebApplCore`;
I added a class library to the solution - `Models`;
I added a class library to the solution - `DBRepository`.

Project `WebApplCore` - ASP.NET Core;
Class Library `Models`, `DBRepository` - Net.Standard 2.0.

Conditional notations for "tests": 
- "+" - `project` is included in the `decision`;
- "-" - `project` is not included in the `decision`.


Test 1.
WebApplCore - "+";
Models - "+";
DBRepository - "-".
Result: debugging works stably. Turning off debugging does not occur.


Test 2.
WebApplCore - "+";
Models - "-";
DBRepository - "+".
Result: debugging works stably. Turning off debugging does not occur.

Test 3. !!!
WebApplCore - "+";
Models - "+";
DBRepository - "+".
Result: debugging does not work stably !!!. After ~10 seconds, debugging automatically stops.

Question.
Why in **Test 3.!!!** does debugging turn off?

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