I used mgcv package for analysis and I use the code below:

model1<-gam(fm_xsetz~total_pm2.5, data=analysis)

I can use summary(model1) to see the results or extracting estimates, se and pvalue and other things. However, when I try to view the results from the right path(global envrionment) i get the following warning:

Error in if (more || nchar(output) > 80) { : missing value where TRUE/FALSE needed

I saw some similar problem when I google, for example, when use the following code

library(geostatsp) data(swissRain)

Same problem happens.

Can anyone help me to figure out the problem?

Thank you so much!