fMRIPrep Feildmap processing error: sdc_wf.pepolar_unwarp_wf.prepare_epi_opposite_wf.merge

Hello,

I am consistently getting an error when including a reverse phase encoded image for distortion correction (ie as a fieldmap), as indicated in the attached screenshot, taken from the output html file. I don’t think there is any deeper underlying issue, and everything works perfectly when I do not include this (ie., remove the fmap directory and run everything). It appears from the messaging in the terminal that the fieldmap file is read in and recognized, as are the linked EPIs. Thank you for your help!
(upload://jpgPOQZKK3e9bWrq1lMPHSbv9Z6.png)