Loo_subsample error for ordinal brms model

Hi! I’m trying to cross-validate a big ordinal brms model using loo_subsample() but it crashes after a while throwing this error: Error in q[, 1L] : incorrect number of dimensions.

I could reproduce the error in one of the examples in the brms::brm documentation (I’m using brms 2.17.0 and loo 2.4.1, session info below).

fit2 <- brm(rating ~ period + carry + cs(treat),
            data = inhaler, family = sratio("logit"),
            prior = set_prior("normal(0,5)"), chains = 2)


loo runs fine, but it is unfeasible for my dataset due to its size.

Any ideas? Thanks!

Session info:

R version 4.0.5 (2021-03-31)
Platform: x86_64-w64-mingw32/x64 (64-bit)
Running under: Windows 10 x64 (build 19042)

Matrix products: default

[1] LC_COLLATE=English_United Kingdom.1252  LC_CTYPE=English_United Kingdom.1252   
[3] LC_MONETARY=English_United Kingdom.1252 LC_NUMERIC=C                           
[5] LC_TIME=English_United Kingdom.1252    

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

other attached packages:
 [1] bayesplot_1.8.1   wesanderson_0.3.6 usethis_2.1.6     tidyr_1.1.3      
 [5] tidybayes_3.0.1   tibble_3.1.2      testthat_3.1.4    stringr_1.4.0    
 [9] stringdist_0.9.8  scales_1.1.1      rlang_1.0.4       rmarkdown_2.11.1 
[13] readxl_1.3.1      purrr_0.3.4       papaja_0.1.1      tinylabels_0.2.3 
[17] patchwork_1.1.1   multilex_1.0.1    mice_3.13.0       lubridate_1.7.10 
[21] knitr_1.33        keyring_1.2.0     janitor_2.1.0     here_1.0.1       
[25] gt_0.2.2          ggsci_2.9         ggplot2_3.3.5     forcats_0.5.1    
[29] dplyr_1.0.7       conflicted_1.1.0  brms_2.17.0       Rcpp_1.0.6       
[33] arrow_8.0.0       tarchetypes_0.3.0 targets_0.7.0    

loaded via a namespace (and not attached):
  [1] utf8_1.2.1           formr_0.9.1          tidyselect_1.1.1     lme4_1.1-27.1       
  [5] htmlwidgets_1.5.3    grid_4.0.5           munsell_0.5.0        codetools_0.2-18    
  [9] DT_0.19              miniUI_0.1.1.1       withr_2.5.0          Brobdingnag_1.2-6   
 [13] colorspace_2.0-2     highr_0.9            rstudioapi_0.13      stats4_4.0.5        
 [17] Rdpack_2.3.1         labeling_0.4.2       emmeans_1.6.3        rstan_2.21.2        
 [21] bit64_4.0.5          farver_2.1.0         bridgesampling_1.1-2 rprojroot_2.0.2     
 [25] coda_0.19-4          vctrs_0.3.8          generics_0.1.0       xfun_0.24           
 [29] R6_2.5.0             markdown_1.1         gamm4_0.2-6          projpred_2.0.2      
 [33] cachem_1.0.5         assertthat_0.2.1     promises_1.2.0.1     googlesheets4_0.3.0 
 [37] gtable_0.3.0         processx_3.5.2       splines_4.0.5        gargle_1.1.0        
 [41] broom_0.7.8          checkmate_2.0.0      inline_0.3.19        yaml_2.2.1          
 [45] reshape2_1.4.4       abind_1.4-5          threejs_0.3.3        crosstalk_1.1.1     
 [49] backports_1.2.1      httpuv_1.6.1         rsconnect_0.8.24     tensorA_0.36.2      
 [53] tools_4.0.5          ellipsis_0.3.2       posterior_1.1.0      RColorBrewer_1.1-2  
 [57] ggridges_0.5.3       plyr_1.8.6           base64enc_0.1-3      visNetwork_2.1.0    
 [61] ps_1.6.0             prettyunits_1.1.1    zoo_1.8-9            fs_1.5.2            
 [65] magrittr_2.0.1       data.table_1.14.0    ggdist_3.0.0         colourpicker_1.1.0  
 [69] childesr_0.2.1       googledrive_1.0.1    mvtnorm_1.1-2        matrixStats_0.60.1  
 [73] shinyjs_2.0.0        mime_0.11            evaluate_0.14        arrayhelpers_1.1-0  
 [77] xtable_1.8-4         shinystan_2.5.0      gridExtra_2.3        rstantools_2.1.1    
 [81] compiler_4.0.5       V8_4.2.0             crayon_1.4.1         minqa_1.2.4         
 [85] StanHeaders_2.21.0-7 htmltools_0.5.1.1    mgcv_1.8-33          later_1.2.0         
 [89] RcppParallel_5.1.4   DBI_1.1.1            MASS_7.3-53          boot_1.3-27         
 [93] Matrix_1.3-2         brio_1.1.3           cli_3.3.0            rbibutils_2.2.8     
 [97] parallel_4.0.5       igraph_1.2.6         pkgconfig_2.0.3      job_0.3.0           
[101] svUnit_1.0.3         dygraphs_1.1.1.6     estimability_1.3     snakecase_0.11.0    
[105] distributional_0.2.2 callr_3.7.0          digest_0.6.27        cellranger_1.1.0    
[109] curl_4.3.2           shiny_1.6.0          gtools_3.9.2         commonmark_1.7      
[113] nloptr_1.2.2.2       lifecycle_1.0.1      nlme_3.1-152         jsonlite_1.7.2      
[117] cmdstanr_0.4.0.9000  viridisLite_0.4.0    fansi_0.5.0          pillar_1.6.1        
[121] lattice_0.20-41      loo_2.4.1            fastmap_1.1.0        pkgbuild_1.3.1      
[125] glue_1.6.2           xts_0.12.1           diffobj_0.3.5        shinythemes_1.2.0   
[129] bit_4.0.4            stringi_1.7.8        sass_0.4.0           memoise_2.0.1       
[133] renv_0.13.2