Line 18 from your Form 8959 should flow to your Form 1040, Line 62.
If you have an amount on Line 24 of Form 8959, this amount should flow to your Form 1040 Line 64.
If you have an amount on Line 18 of your Form 8959 but it is not flowing to your Form 1040, Line 62, I would need to request a diagnostic copy of your Tax Return to look into the issue further. Please go to your return and click on tax tools>>tools>>share file with agent. Then share the code with me.