Further investigation revealed that when the external SD card (/storage/sdcard1) is mounted, vold looks to see if it is flagged as "providesAsec" and if so mounts the /storage/sdcard1/.android_secure which points the way to the apps on the sdcard. In the case of codinalte, /storage/sdcard1 is not flagged as "providesAsec" so the secure area where apps are stored is never mounted and /mnt/secure/asec is just an empty dir attached to the root "/" mount with no actual space and it's read only. That's why when moving "apps to sd" it reports "not enough space". I've got this corrected and I didn't want to build and entire release for this fix so I made a little patch that can be flashed via recovery. This fix will be included in future builds. This patch is for "CARBON-5.1.1-METICULUS-20160712-0645-codinalte" only.
Patch is on the download page next to the build.