json request api unexpected error message

[Szűcs Roland]

Dear SOLR users,

I tried to use the following json request in python:
json={
    "params":{
        "q": 'Roy',
        "defType": 'edismax',
        "qf":'name_suggest brand_suggest',
    }
}

requests.post(COLLECTION + '/autocomplete', json=json).json()
The result was inline with my expectations. I know, the json request api
supports 'query' instead of 'q' as a top level parameter but I just wanted
to see how it works.

As I add one more parameter and having an updated json:
json={
    "params":{
        "q": 'Roy',
        "defType": 'edismax',
        "qf":'name_suggest brand_suggest',
        "boost":get_boost_text(profile)
    }
}
I get a weird seemingly unrelated error message:

"no field name specified in query and no default specified via 'df' param".

It is strange as I had qf defined in both versions and once I get an error
once not.
get_boost_text returns the following string:

'query({!v=" all_text:One^167.7 all_text:Macska^142.1
all_text:felnőtt^106.4 all_text:Cat Vital^58.9 all_text:Profine^40.4
all_text:Royal Canin^24.2 all_text:Purina^21.5
all_text:ivartalanított^21.2 all_text:fajtatáp^10.2
 all_text:Prevital^10.1 name:búza^266.4 name:lazac^103.6
name:macska^102.3 name:cat^60.9 name:profine^40.4 name:10kg^38.6
name:kitten^27.6 name:canin^24.2 name:fhn^23.4 name:chow^21.5
description:bifensis^366.0 description:jövő^307.9
 description:ivartalanítot^266.4 description:egészséges^233.5
description:is^232.4 description:cat^228.8 description:fellépő^225.2
description:alkalmasak.^224.4 description:erőszakmentes^224.4
description:gyököket.bőr^224.4 "})'.

Any idea, why it happens that adding boost parameter makes the query
invalid with an error message not related to the boost?

Thanks in advance,

Roland