yes there is a chance that u could do to much of a wc at once, likely eh prob not. it all depends on the water thats in there tds and what your replacing it with it could put them into osmotic shock but ive seen some off the chart #'s back to super low without issues its all on how its done. think of it as the same way u acclimate a fish to your tank from a different water peramiter, if the tank was super bad and u put it into a prestine tank it very well could and has happend just not common.
the real thing that u need to do is test to see what it really is go step by step and eliminate possibilitys, if it was a o.d. on excel, osmoshock(not as likely), ammonia build up(possible with out knowing how your tank is stocked), or some unknown from the water, tempature shock? kinda hard to say without the right info... its kinda a guess crapshoot so take ur pick..