This is a long-time pending issue. Some structures for tRNAs (see ChEBI IDs in the attached file) are empty (except for a strange character I cannot read) and with status OK.
This results in images with just a parallelogram in them, which are not shown in ChEBI website but served for Rhea (see some examples in the other attached file) and enzymeportal.
In the list of Rhea examples you will see that other tRNAs have no structure, and there is no image shown (which is nicer).
Is there any reason to keep those structures with status OK? If not, would you please delete/obsolete them in order to avoid parallelograms? :)