Terrain follow [guided mode]

Hello everyone,
need advice on Terrain following in Guided mode.
I set the TERRAIN_ENABLE parameter to 1,
In Pixhawk, I uploaded map tiles of 30m to the APM/TERRAIN folder on SD card. Version of FW is 4.xx. The GCS is connected to the AP and the GPS coordinates is send to AP and the altitude is set to 25m. When switching to Guided mode, the drone follows the GCS, but if the terrain rises by 15m, the drone still follows the station, but only at a altitude of 10m. Can you tell me where I’m doing wrong?
EK2_ALT_SOURCE or EK3_ALT_SOURCE is set to 0, EK2_RNG_USE_HGT or EK3_RNG_USE_HGT is set to -1.
Thank you for your help.

You should use ArduCopter 4.3.1-rc1