The below error only occurs after we use the import fMRIprep function. If we upload the data manually it runs smoothly. The error appears to occur when CONN is "loading ROIs" and possibly more specifically during mask erosions. Below is the error. 

Error using cat
Dimensions of arrays being concatenated are not consistent.
Error in conn_process (line 853)
covariates=cat(2,covariates.data{defaultcov});
Error in conn_process (line 50)
case 'setup', conn_disp(['CONN: RUNNING SETUP STEP']); conn_process([0:4,4.5,5]);
Error in conn (line 6306)
conn_process(processname); ispending=false;
Error in conn_menumanager (line 121)
feval(CONN_MM.MENU{n0}.callback{n1}{1},CONN_MM.MENU{n0}.callback{n1}{2:end});
CONN21.a
SPM12 + DAiSS DEM FieldMap MEEGtools
Matlab v.2018b
project: CONN21.a
storage: 1385.5Gb available
spm @ /Users/SNAP/Documents/MATLAB/spm12
conn @ /Users/SNAP/Documents/MATLAB/conn