> For the complete documentation index, see [llms.txt](https://knowledgebase.fabricdata.com/xytech/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://knowledgebase.fabricdata.com/xytech/rest-api-v3/known-issues.md).

# Known issues

Issues currently known to affect API v3. Each entry describes the behaviour you will see, and the recommended approach until it is addressed.

{% hint style="success" %}
**Fixed in 26.5HF1 / 26.5M.** The four `POST /query` filter defects previously listed here - `$`-prefixed operators being silently ignored, a second condition on the same field replacing the first, an `"or"` group combining its `conditions` with AND instead of OR, and a second sibling `"or"` group discarding the first - are corrected as of 26.5HF1 and 26.5M. See [Filtering reference](/xytech/rest-api-v3/api-v3-user-guide/filtering-reference.md) and [Querying with POST](/xytech/rest-api-v3/api-v3-user-guide/querying-with-post.md) for the current syntax. On a build earlier than 26.5HF1 / 26.5M, all four defects are still present.
{% endhint %}

**Filter groups: nesting an `or` group inside another `or` group is rejected**

An `"or"` group cannot contain another `"or"` group - the request is rejected with an error naming the field rather than the filter being silently altered. This holds up to two levels of alternation; see [Querying with POST](/xytech/rest-api-v3/api-v3-user-guide/querying-with-post.md) for the shapes this allows and disallows.

The same limitation applies to the `$or` filter in API v2.