The items can be bought, the text message "You have successfully bla bla +50HP" appears but the MaxHP are not increased. Even with reg items/skills or lifeleech skills they do not increase. I randomly tested it with Blood Hunter and Warden buying health, bracers and ring and leeching with Blood Hunter, the HP remained at 100.
For the Fortified Bracers there is no text in chat, cause the items in shopmenu2 and itemsinfo2 are all "translation failed" but the item is listed in my playerinfo so it was bought successfully.

Edit: I use the "afk plugin", players can join spectator by writing "afk". After rejoining a team after being "afk" I spawned with the 3 Items with 160HP. MaxHP are increased after respawn, unfortunately the shopmenu(1) items disappear after dying The Fortified Bracers of course remained, so I always respawn with 110HP now.

CS:S with War3Source 1.2.3.6, the latest full release
CS:S is running with Deathmatch, just for the case that's important to know.

Races which spawn with increased MaxHP like Human Alliance or Naix Lifestealer work fine.

I don't think that DM causes the problem here, because the items should increase the HP when they are bought but the HP are not increased until the next respawn. If it's a new round respawn and the player survived the round he keeps the items and spawns with correctly increased HP, but if he dies and respawns he lost the periapt and only spawns with +10HP from the bracers. This works for DM and non-DM.
Rejoining with the "afk plugin" is like having survived the round. I keep all the items and respawn without any problems with correctly increased HP from both items.

I hope you can understand what I try to explain.

I can try the svn and keep you updated about it.

Quick update, before anyone starts a big search in the sourcecodes...

I'm having a huge try and error session with and without deathmatch. Unfortunately my testserver hates me and crashes all the time.
As far as I got now it seems like deathmatch actually causes the problem.


Edit:
Finally got the testserver running well.
On the testserver everything is working correctly. CSDM does not cause any problems. In the worst case the main server needs a reinstall...
Sorry for the false alarm.