What scanner are you using? Are you sure you are allowing the scanner time enough to scan or signals?
Is the 1525 running both 2.4Ghz and 5Ghz at the same time or single radio?
Just because the 1525 isn't being seen on the scanner, maybe that the scanner is detecting the 868L signal even though it's farther away. Could be some 20/40Mhz operation going on that the scanner finds better with the 868L.
Try a different scanner?
Does the 1525 have any HT20/40 Co-existence options, maybe under Wireless or Advanced Wireless?