DC Fuse/holder Query

I've got a Victron system with a sizable MPPT 250/70 and 6 panels installed. In the DC distribution box there's 2 surge arresters and then a DP 1000V/32A fuseholder that was running a pair of 1000V/32A fuses. A few months back one of the DC fuses popped. Our installer told me it was most likely due to the overcast day we had and that can make the panel voltage spike at times. After some driving around and getting spare fuses replaced the one that was popped and was fine from there. Last week however it happened again and it was quite evident there is massive charring from some sparking inside the fuseholders. Did'nt have spare fuseholders at the time (some shortage currently) but put another fuse in and it held all up until today when it blew again and the smell was quite evident. 

Found some spare fuseholders that someone was hiding that are 1000V/30A holders. I only have 32A fuses left. Should it be a problem? Does anyone know perhaps why this is happening? It feels to me like there might be more to it but my installer is quite awesome with support and ensures me its either i didnt put the fuses back properly or a panel voltage spike, but something about it feels a bit off like there might be more to it - why would the fuseholders be charred to hell and back (unless it was me not putting it back all the way?)

Thanks