[Python SDK | API] Inconsistent results with files_search_v2

We are experiencing inconsistent results with the files_search_v2 function with both the Python SDK and API. An example is if we are searching for a particular file: '/Media Coordination/VERSIONING/Graveyard_Carz_TE00000114/S06/Subs/TE00000114_06_0011_A2_S_FRA.srt'

If we search for a particular string eg. 'TE00000114_06_0011_A2' we are returned a list of results which does not include the file in question:

['/Media Coordination/VERSIONING/Graveyard_Carz_TE00000114/S06/Subs/TE00000114_06_0011_A2_S_NLD.srt', '/Media Coordination/VERSIONING/Graveyard_Carz_TE00000114/S06/Subs/TE00000114_06_0011_A2_CC_ENG.srt', '/Media Coordination/VERSIONING/Graveyard_Carz_TE00000114/S06/Subs/TE00000114_06_0011_A2_S_TUR.srt', '/Media Coordination/VERSIONING/Graveyard_Carz_TE00000114/S06/Subs/TE00000114_06_0011_A2_S_CMN.srt', '/Media Coordination/VERSIONING/Graveyard_Carz_TE00000114/S06/Subs/TE00000114_06_0011_A2_S_CMN_FMT.srt']

If we 'widen' the search to now search for the following string 'TE00000114_06_0011_A', the following and expected results are returned:

['/Media Coordination/VERSIONING/Graveyard_Carz_TE00000114/S06/Subs/TE00000114_06_0011_A2_S_FRA.srt', '/Media Coordination/VERSIONING/Graveyard_Carz_TE00000114/S06/Subs/TE00000114_06_0011_A2_S_NLD.srt', '/Media Coordination/VERSIONING/Graveyard_Carz_TE00000114/S06/Subs/TE00000114_06_0011_A2_CC_ENG.srt', '/Media Coordination/VERSIONING/Graveyard_Carz_TE00000114/S06/Subs/TE00000114_06_0011_A2_S_TUR.srt', '/Media Coordination/VERSIONING/Graveyard_Carz_TE00000114/S06/Subs/TE00000114_06_0011_A2_S_CMN.srt', '/Media Coordination/VERSIONING/Graveyard_Carz_TE00000114/S06/Subs/TE00000114_06_0011_A2_S_CMN_FMT.srt']

A simplified version of the function here: 

def dropbox_find_local():
    dropbox_vers_path = '/Media Coordination/VERSIONING'
    search_string = 'TE00000114_06_0011_A'
    sub_ext = '.srt'
    def process_entries(entries):
        for entry in entries:
            metadata = entry.metadata.get_metadata()
            local_file = metadata.path_display
            local_list.append(local_file)
    local_list = []
    search_opt = SearchOptions(path=dropbox_vers_path, file_extensions=[sub_ext.lstrip('.')], filename_only=True)
    result = dbx.files_search_v2(search_string, options=search_opt)
    process_entries(result.matches)
    while result.has_more:
        result = dbx.files_search_continue_v2(result.cursor)
        process_entries(result.matches)
    print(local_list)

This same behaviour can be reproduced if we use the web API which uses the same files_search_v2 endpoint:
https://www.dropbox.com/search/work?path=%2FMedia+Coordination%2FVERSIONING&query=TE00000114_06_0011_A2 (Missing results)
https://www.dropbox.com/search/work?path=%2FMedia+Coordination%2FVERSIONING&query=TE00000114_06_0011_A (Expected behaviour)