Thank you for the example file.
Please update Brainstorm to get this fix: https://github.com/brainstorm-tools/brainstorm3/commit/6858360073a027d3b02b8bbbc1fcccdda0fa9365
It adjusts the number of time samples based on the sampling frequency defined to be used in Brainstorm, instead of relying only on the timestamps of the first and last samples in the NIRS file. This may cause a slight difference in timing in Brainstorm, with respect to what is available in the NIRS file.
A warning is displayed in the Matlab command window to show these differences. Example for this file:
BST> WARNING: Unstable sampling frequency in NIRS file.
BST> | MEAN: mean(1./diff(t))=75.000187500460 Hz | STD: std(1./diff(t))=0.000000000217 Hz
BST> | Time of last sample reported in the NIRS file: 1152.063786500000 s
BST> | Time of last sample as imported in Brainstorm: 1152.037865000000 s
@edelaire Please let me know if you think there is any issue with this approach.