I have a problem converting POSIXct to character and back in POSIXct in R. I run the following code:

time_seq_01 <- seq(as.POSIXct("2012-10-28 02:00:00"), by = 900, length.out = 10)
time_seq_02 <- as.character(time_seq_01)
time_seq_03 <- as.POSIXct(time_seq_02)

or equivalent:

time_seq_01 <- seq(as.POSIXct("2012-10-28 02:00:00"), by = 900, length.out = 10)
time_seq_02 <- format(time_seq_01,usetz = TRUE)
time_seq_03 <- as.POSIXct(time_seq_02)

This are the timestamps in 2012 when the daylight saving transition from Central European Summer Time (CEST) to Central European Time (CET) occurs (Last Sunday in October 02:00 - 03:00).

When I call these elements I get

time_seq_01
[1] "2012-10-28 02:00:00 CEST" "2012-10-28 02:15:00 CEST"
[3] "2012-10-28 02:30:00 CEST" "2012-10-28 02:45:00 CEST"
[5] "2012-10-28 02:00:00 CET"  "2012-10-28 02:15:00 CET" 
[7] "2012-10-28 02:30:00 CET"  "2012-10-28 02:45:00 CET" 
[9] "2012-10-28 03:00:00 CET"  "2012-10-28 03:15:00 CET" 
time_seq_02
[1] "2012-10-28 02:00:00 CEST" "2012-10-28 02:15:00 CEST"
[3] "2012-10-28 02:30:00 CEST" "2012-10-28 02:45:00 CEST"
[5] "2012-10-28 02:00:00 CET"  "2012-10-28 02:15:00 CET" 
[7] "2012-10-28 02:30:00 CET"  "2012-10-28 02:45:00 CET" 
[9] "2012-10-28 03:00:00 CET"  "2012-10-28 03:15:00 CET" 
time_seq_03
[1] "2012-10-28 02:00:00 CEST" "2012-10-28 02:15:00 CEST"
[3] "2012-10-28 02:30:00 CEST" "2012-10-28 02:45:00 CET" 
[5] "2012-10-28 02:00:00 CEST" "2012-10-28 02:15:00 CEST"
[7] "2012-10-28 02:30:00 CEST" "2012-10-28 02:45:00 CET" 
[9] "2012-10-28 03:00:00 CET"  "2012-10-28 03:15:00 CET"

The creation of a POSIXct sequence does work correctly (time_seq_01) the transition to character also (time_seq_02). However the transition back from character back to POSIXct produces wrong timezone (CET/CEST) values (time_seq_03

r posixct
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