Here's what I get when I pull data from those two fields:
Property
CM_4
(L_Status=1_0,3_0),(L_DisplayId=E4045624),~(LA1_LoginName=ENONMBRS),((LM_Char1_2=.EMPTY.)|(LM_Char1_2=N))
LM_Dec_28,LM_int4_35
<rets replycode="0" replytext="SUCCESS" >="" <delimiter="" value="09"/>
<columns> LM_Dec_28 LM_int4_35 </columns>
<data> 0.59 25774 </data>
</rets>
Update 2017-06-23: Checked (L_DisplayId=E4045783)
Here's my result. I checked the listing in paragon and the "Land Size SF" field LM_int4_35 is blank there too so RETS is returning exactly what is in the listing.
<rets replycode="0" replytext="SUCCESS" >="" <delimiter="" value="09"/>
<columns> LM_Dec_28 LM_int4_35 </columns>
<data> 0.92 </data>
</rets>