A Challenge to Texas Right of Redemption

[Cory Damon]

We know that the redemption period for tax deeds in Texas is one of the following:

1) 2 years for homestead and ag exempt
2) 180 days for all others

However, it appears that it is possible for a tax sale to be contested beyond the redemption period - especially the NON homestead/ag properties. I especially want to thank @Roy Oliphant for pointing this out in one (or many) of his posts. Roy's comments got me curious and I wanted to get to the bottom of this. Please add-to and correct my ignorance below. 

I'm not a lawyer so the code if like hieroglyphics to me, but here are portions of the Texas Tax Code that I found helpful. 

Section 34.21 goes on to spell out the redemption period that most of us are familiar with. But as I read the highlighted sections above, I'm seeing two different interpretations; 1) anyone that has a right to the property and was not notified [33.54(b)] is not bound by ANY limitations period, 2) anyone that falls into the first interpretation actually has a 2 year limitation [34.08(c)]. Notice that this is outside of the homestead/non-homestead redemption sections found in [34.21].

I'm sure I don't understand this correctly and I have other questions, but let's start with this. Any RE attorneys want to comment? 

Thanks y'all