single list estate issues

i have following 3 rails classes, stored table, controlling rails' unparalleled list inheritance.

class template < activerecord::base
class thingtemplate < template
class stockthingtemplate < thingtemplate

if i have stockthingtemplate id 150 following i should logically means this:

thingtemplate.find(150)
=> #returns me stockthingtemplate

and fact works, sometimes

when works, generates following sql query:

select * templates where (templates.`id` = 159) ( (templates.`type` = 'thingtemplate') (templates.`type` = 'stockthingtemplate' ) )

when doesn't work, generates following sql query:

select * templates where (templates.`id` = 159) ( (templates.`type` = 'thingtemplate') )

the sql doing ostensible to, nonetheless doubt is, since generating set sql time, opposite set another time. it's literally accurate same code.

notes:

i've already attempted require 'stock_thing_template' several places. presumably effect, causes problems

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