It appears that the section covering the redemption of HOA lien foreclosures in the Texas Property Code is 209.011. That states the redemption period is "not later than the 180th day after the date the association mails written notice of the sale to the owner and the lienholder". However, there may be more recent court cases that the insurers are using to make their decision to wait two years. There may be other factors (such as a bankruptcy) that may be influencing their view on the redemption period.

To my knowledge, there is no obligation for a title insurer to explain why they decide not to insure a transaction. However, I do not know why they would not explain their reasoning so that a course of corrective action could be planned.

If all of the underwriters are refusing, then there is probably a good reason to do so. If you have not 'shopped' with all of the underwriters, I would keep checking.