ASP .Net Core with MemoryCache

I use MemoryCache with ASP .Net Core. I want to save List<> in cache, but got strange problem.

1. Forming List;

2. Succesfully saved it in cache:

    TrySetEntity(typeof(SkvBase).Name, _wells, _cacheEntryOptions);
   
    public virtual void TrySetEntity(string key, IList<TEntity> createItem, MemoryCacheEntryOptions cacheEntryOptions)
    {
        using var entry = _cache.CreateEntry(key);
        entry.SetOptions(cacheEntryOptions);
        entry.Value = createItem;
        _cache.Set(
        key,
        entry,
        new CancellationChangeToken(_resetCacheToken.Token));
    }
   

3. Cleared List!

4. Cache values was cleared too!! Why???

    public virtual TWell Get<TWell>(string key)
    {
        _cache.TryGetValue<TWell>(key, out var entry);
        return entry;
    }