Update: Just today I got a telescope. But that does not change my feelings. 
I’ve gotten the A+ on the majority of our rare titans and never once in 2 years got the special item.
Yeah it took me like 19 months before I got my first bonus item… Then got another 2 in the last 8 months… Go figure 
My 3* & 4* non-farmables since 3/9 …
Notes: 4* underlined, from titans with red. Does not count rare quests or challenge events.
Did you have a log of every AM from titan for the last 90 days? If not, then start it.