now work fine, I don´t know why.
The PDF's Structure Tree (viewed via the Tags panel) establishes accessibility; not read order.
PDF is not HTML - there are no 'anchor' tags. PDF elements ("tags") are identified in ISO 32000-1 (see 14.8).
Accessible PDF is defined by ISO 14289-1.
For tables you want to master the content in a regular table in an authoring application that has good tag management for output of the tagged PDF.
Doing so will provide you with a proper tagging of the the table such that minimal post-processing with Acrobat Pro is needed (there will be some required regardless - just not a lot of it).
Trying to manually tag a "table" in a PDF is -- well just not worth it. Especially as there is no "undo" for work done in the structure tree.
Rather than labor under conceptual errors, false/misleading assumptions, etc. when striving to provide accessible PDF you want to obtain the reference information that provides the real, no baloney "play book".
Frankly, anything less is "play acting".
For those who desire to / need to provide accessible PDF success is predicated in having and understanding the essential reference material.
ISO 32000-1 (14.8 in particular).
Document Management – Portable Document Format – Part 1: PDF 1.7, First Edition
Adobe (Jul 2008)
This document is an ISO approved copy of the ISO 32000-1 Standards document. By agreement with ISO, Adobe Systems Incorporated is allowed to offer this version of the ISO standard as a free PDF file on their own Web site.
It is not an official ISO document but the technical content is identical; the page and section numbers are also preserved.
ISO 14289-1 (PDF/UA-1)
This you will have to purchase ($104) from the ANSI Web Store.
The Matterhorn Protocol.
The resources for Accessible PDF at the AIIM site.
PDF/UA-1 Technical Implementation Guide: Understanding ISO 14289-1 (PDF/UA-1)
PDF/UA-1 Technical Implementation Guide: Understanding ISO 32000-1 (PDF 1.7) (under development)
Achieving WCAG 2.0 with PDF/UA
(WCAG 2.0 for PDF IS PDF/UA-1)