No, it's not a bug. Timber sales are typically reported as capital gains on Form 8949 and Schedule D if held as an investment, or as ordinary income on Schedule F for farmers/business inventory. To report timber sales as a capital gain you report them the same way you would gains/losses reported on Form 1099-B - that's why the software takes you to 1099-B type reporting. For step-by-step instructions on how to enter your timber sales click on the following link: Where do I enter income from a timber sale?
For information on the taxation of timber sales see https://www.timbertax.org/