-I added a space at the end of a subfield $9, saved the record, and attempted it view it in the OPAC. None of the information from the 856 field displayed.
-I went into flat-text editor and added a space, then saved. Again, the 856 information did not display in the OPAC. I mention flat-text editor because it would be easier to add trailing space in flat-text without noticing you've done so.
-The records I altered by adding the trailing space did appear in OPAC searches.
Tested on master.
-I added a space at the end of a subfield $9, saved the record, and attempted it view it in the OPAC. None of the information from the 856 field displayed.
-I went into flat-text editor and added a space, then saved. Again, the 856 information did not display in the OPAC. I mention flat-text editor because it would be easier to add trailing space in flat-text without noticing you've done so.
-The records I altered by adding the trailing space did appear in OPAC searches.