two [once] in the same template

hi,
i have a problem using [once] in a template two times.

i dont know why but the second [once] isnt processed.

i want to fill a html tag with first on the first found image, that work well on the first time i do this, at the second time in the same template with completely same code just an other field i wont work.

here is the code part:

<div class="bilderbox">
	
	

	<div class="topogal">
		<div class="detailitemheader">
			Topobilder: 
		</div>
		
		<div class="detailitem topoimg">
			<ul class="topogals">
				<div class="avia-gallery">
				[each topobilder]
					<li class="topo [once]first[/once] ">
						<a href="{@_src.full}" data-lightbox="Topobilder{@topobilder.id}" class="lbimg " title="Topobilder: {@bergname} - {@routenname}" rel="Topobilder">
							<img data-lightbox="Topobilder" src="{@_src}" class="lbimg [once]firstimg[/once]" />	
						</a>
					</li>
				[/each]
				</div>
			</ul>
		</div>
	</div>

	
	<div class="picgal">
		<div class="detailitemheader">
			Bildergalerie:  
		</div>
		
		<div id="galbox" class="detailitem galerie">
			<ul class="picgals">
				<div class="avia-gallery">
				[each bildergalerie]
					<li class="gal [once]first[/once] ">
						<a href="{@_src.full}" data-lightbox="Tourenbilder {@bildergalerie.id}" class="lbimg " title="Bildergalerie: {@bergname} - {@routenname}" rel="Tourenbilder">
							<img data-lightbox="Tourenbilder {@bildergalerie.id}" src="{@_src}" class="lbimg [once]firstimg[/once]" />	
						</a>
					</li>
				[/each]
				</div>
			</ul>
		</div>
	</div>

</div>

can sommeone tell me why?

thx

s.

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