Numbers in RTL tables do not work as expected

Question

I am not able to put numbers as the first characters in a table cell in a RTL document without adding unwanted markers and spaces, or getting checking errors. These errors seem to occur using any type of digit following a table cell marker. I want to know: Is this a bug, a feature, or am I doing something wrong?

Case 1 A table cell does not display at all if numbers directly follow the cell marker:

\tr \tc1 123 \tc2 456

Case 2 The table cell displays correctly if a left-to-right character is added, however a Number Settings error is raised:

\tr \tc1 [LTR]123 \tc2 [LTR]456

Case 3 The table cell displays correctly and no error is raised if a left-to-right character and space is added, however this adds extra space to the cell. C.f.:

\tr \tc1 [LTR] 123 \tc2 [LTR] 456

\tr \tc1 [LTR]123 \tc2 [LTR]456