Chiming in from April 2025 to say that this bug still exists, and "the phone people" that the expert above advised to reach out to are clueless about it.
Turbotax' logic seems to generate and include form 8949 if and only if the income thresholds for additional Medicare tax liability are reached. However, this is not the only use of form 8949, as the original poster highlighted. If for any reason too much Medicare tax was withheld from a W-2 or other, form 8949 is the form where the overwithheld amount is calculated and flowed through to the 1040 as a credit for tax withholding.
So, if a filer's income is not high enough to trigger additional 0.9% liability, but the filer is owed medicare withholding refund, this is an unworkable situation where the tax filer loses out on credit they are owed. This can be reproduced by manipulating the W-2 medicare wages amount to be higher or lower than the income threshold, which makes form 8949 appear or disappear.
Intuit should immediately fix this by requiring the form to be included if EITHER 1) income is high enough to generate additional tax liability, OR 2) there exists a nonzero amount of Additional Medicare Tax withholding (Part V of Form 8959).
The especially frustrating and stupid part of this is that the form exists in the background, viewable in the desktop product by clicking Open Form in Forms view. But it's not listed on the left side column of forms that make up the actual return!
