Error: Multiple @serializers specified for one function

[McCompexpert]

Getting an error message in plumberize.R file:

> r <- plumb('blockchain-node-server.R')
Error in stopOnLine(lineNum, line, "Multiple @serializers specified for one function.") : 
  Error on line #95: '#* @serializer custom_json' - Multiple @serializers specified for one function.

My session Info:

> sessionInfo()
R version 3.4.0 (2017-04-21)
Platform: x86_64-w64-mingw32/x64 (64-bit)
Running under: Windows >= 8 x64 (build 9200)

Matrix products: default

attached base packages:
[1] stats     graphics  grDevices utils     datasets  methods   base     

other attached packages:
[1] plumber_0.4.4 uuid_0.1-2    httr_1.3.1    jsonlite_1.5  digest_0.6.13

loaded via a namespace (and not attached):
[1] compiler_3.4.0 R6_2.2.2       tools_3.4.0    rstudioapi_0.7 Rcpp_0.12.13   crayon_1.3.4   stringi_1.1.5  httpuv_1.3.5  

[McCompexpert]

Can be closed: answered by plumber developers:
Issue