Collector achievement bug

[VibePulse]

As the title say, I'm having a bug with achievement.
When I completed my game, I wanted to have all achievements so I used walktrough which I found here somewhere on steam forum to find missing wolves.
The thing is, I completed the game 2nd time by using pointers in walktrough of all wolf locations and I'm still missing one!
Went to complete the game 3rd time using youtube to make sure I have them all but every location is already done!
I'm frustrated for not having a perfect game because of this!
I even dug in my save files after that to try to "cheat" my way with it but even with editing save file I'm not getting that last achievement...

Here's what it say:

<?xml version="1.0" ?><profile><Achievements><elements count="20"><e><Achievement><Name><![CDATA[Collector]]></><IsSecret>false</><RevealedOnProgress>false</><Failable>false</><ShowProgress>true</><MaxProgress>20</><Revealed>true</><Failed>false</><Achieved>false</><StartedTime>0</><CurrentProgress>19</><PropertyList><elements count="21"><e><property type="string" name="ClickSound"><![CDATA[WolfHowl]]></></><e><property type="bool" name="SecretObject">true</></><e><property type="bool" name="/Locations/l4/Collector">true</></><e><property type="bool" name="/Locations/l5/Collector">true</></><e><property type="bool" name="/Locations/l3/Collector">true</></><e><property type="bool" name="/Locations/l7/Collector">true</></><e><property type="bool" name="/Locations/l8/Collector">true</></><e><property type="bool" name="/Locations/l9/Collector">true</></><e><property type="bool" name="/Locations/l10/Collector">true</></><e><property type="bool" name="/Locations/l12/Collector">true</></><e><property type="bool" name="/Locations/l16/Collector">true</></><e><property type="bool" name="/Locations/l21/Collector">true</></><e><property type="bool" name="/Locations/l19/Collector">true</></><e><property type="bool" name="/Locations/l25/Collector">true</></><e><property type="bool" name="/Locations/l36/Collector">true</></><e><property type="bool" name="/Locations/l38_2/Collector">true</></><e><property type="bool" name="/Locations/l11_new/Collector">true</></><e><property type="bool" name="/Locations/l14/Collector">true</></><e><property type="bool" name="/Locations/l40/Collector">true</></><e><property type="bool" name="/Locations/l42/Collector">true</></><e><property type="bool" name="/Locations/l17/Collector">true</></></></></></><e>

any kind of help will be appreciated!