spq_set(var) and spq_label(var, .overwrite=TRUE) cannot work together

[lvaudor]

For instance:

country_id="wd:Q148" 
result=spq_init() %>%
    spq_set(country=country_id) %>% 
    spq_add("?country wdt:P37 ?language_official") %>% 
    spq_add("?language_official wdt:P424 ?language_official_code") %>% 
    spq_label(country,language_official, .overwrite=TRUE) %>% 
    spq_perform(replace_prefixes=TRUE) 

result has 0 rows

whereas the same query, without the .overwrite=TRUE option does return a result (1 row). Maybe just thow a warning when using spq_set(var) + spq_label(var, .overwrite=TRUE)?