The Wells Fargo reference is talking about an excess traditional IRA contribution and is wrong. As long as the amount contributed for the year to a traditional IRA was no more that the statutory limit for the year (for 2022, $6,000 if under age 50, $7,000 if over age 50), the distribution of the excess after the extended due date of the tax return is not taxable, so no double taxation. Because the excess is not taxable upon distribution, there is also no early-distribution penalty. See section 408(d)(5) of the tax code which indicates that paragraph (1) [inclusion in taxable income] does not apply:
https://www.law.cornell.edu/uscode/text/26/408#d
TurboTax has a way to indicate such a distribution of an excess after the due date. It's done by entering a zero in box 2a of TurboTax's 1099-R form instead of entering the actual amount from box 2a of the Form 1099-R provided by the traditional IRA custodian. TurboTax will then prompt for an explanation statement where you'll explain that the distribution is a nontaxable distribution of the excess after the due date of the tax return for the year for which the contribution was made.
The Motley Fool reference refers to a distribution of the excess from a Roth IRA after the due date of the tax return, but makes a different mistake. Even though it's an excess contribution, the excess contribution adds to Roth IRA contribution basis. Because contribution basis comes out first, the distribution of the excess after the due date consists entirely of nontaxable contribution basis. Again, because it's nontaxable, there is also no early-distribution penalty. TurboTax also handles this distribution correctly by determining on Form 8606 Part III that the distribution is nontaxable and also including it on Form 5329 to reduce the amount of excess in the Roth IRA on which an excess contribution penalty is calculated.
In both the case of an excess traditional IRA contribution and an excess Roth IRA contribution, the nontaxable treatment I've described is consistent with being able to apply the excess as some or all a year's contribution. Applying it as a contribution for some year after the year for which the excess contribution is made is equivalent to taking it out as a nontaxable distribution and then putting it back as a new contribution.
