I don't know Texas law, other than the general prohibitions against direct contributions from corporations, whish seems undisputed. But the relevance is that the money came from corporations like Sears into TRMPAC. So far, nothing illegal. TRMPAC cannot directly donate to candidates, however. So they send money to the RNC, which then goes to candidates. Again, nothing illegal or unusual. Many times there is an understanding to that extent, though nothing specific. I myself have maxed out on candidate only to have them direct me to a state party that I know means they will support that candidate (I don't do it).
But in this case, there is a big difference in the way of legal proof. The check from TRMPAC to RNC was $190,000 - that's attached to the indictment. There was also a written note directing which state campaigns to use it for in the total amount of $190,000 or something close to $200,00 (I have seen both) - the description in the indictment. So now you have proof that it wasn't just a contribution from TRMPAC to RNC that they had no knowledge or control over where it might be used or for what, but one with specific instructions to direct contributions to specified candidates in specified amounts, thereby circumventing the prohibition directly and knowingly,