Sorry, I don't use your platform (i.e. Raspberry Pi), and my knowledge into SNMP is rather limited. So I can't really help you.
Anyway, the correct person to help you is most probably Remy Lebeau himself, as he's currently the "main" coder for Indy. I see that he requested a few more details in order to hep you in your topic at stackoverflow.com.
I guess you should provide your output captures (i.e. mhxFTAb.png) into this stackoverflow topic, in order he can help you and/or suggest a few more tests.
And for your information, in case you don't already know it, here is the "official" forum for Indy:
http://forums2.atozed.com/ . If you plan to open a new topic concerning your problem in this forum, you should give a link to your former topic at stackoverflow (in order Remy Lebeau can identify it). But, please note that Remy Lebeau is also present and active in the stackoverflow forums anyway (so it's not absolutely necessary to open a new topic at atozed.com).
BTW, just by curiosity and because I can't see any indication for it in your posts, do you use a recent version of Indy? The current version and revision are : Indy 10.6.1 rev 5226