NA for p value of intercept in permutation test through permutes package in R

Question

I am looking for how FROH (inbreeding level) change with age, island and year are random. I got the following result and got NA for p value of intercept, what might be the cause of it and how to interpret in such case?? is use of perm.lmer function wrong here??

permmod1<- perm.lmer(FROH ~ age + (1|island) + (1|year) , data = Ad_Data, nperm = 1000, type = "regression", progress = F)

> permmod1
           Factor        LRT         beta         t     p
    1 (Intercept) 3159.75993  0.030081868  6.408866    NA
    2         age   13.51311 -0.001078063 -2.835235 0.003
    
> summary(permmod1)
                Factor               LRT               beta                 t                 p        
             Length:2           Min.   :  13.51   Min.   :-0.001078   Min.   :-2.8352   Min.   :0.003  
             Class :character   1st Qu.: 800.07   1st Qu.: 0.006712   1st Qu.:-0.5242   1st Qu.:0.003  
             Mode  :character   Median :1586.64   Median : 0.014502   Median : 1.7868   Median :0.003  
                                Mean   :1586.64   Mean   : 0.014502   Mean   : 1.7868   Mean   :0.003  
                                3rd Qu.:2373.20   3rd Qu.: 0.022292   3rd Qu.: 4.0978   3rd Qu.:0.003  
                                Max.   :3159.76   Max.   : 0.030082   Max.   : 6.4089   Max.   :0.003  
                                                                                        NA's   :1      
       

    

I looked for data, there is no any NA value, could not figure out whats going on.